| 1. |
- Jansson, Malin, 1978-
(författare)
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The role of stroma-derived substances in breast cancer progression and their function as tumour markers
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: In 2020, more than 2,260,000 women were diagnosed with breast cancer. Most patients are cured with surgery and adjuvant treatment, but despite that, approximately 700,000 women die of the disease every year. The historical focus on breast cancer progression has been on the malignant epithelial cell. However, cancer cells do not grow in isolation. In recent years, the importance of the tumour microenvironment in cancer progression has been highlighted. Perlecan and type IV collagen are basement membrane (BM) proteins in the normal mammary gland, and type I collagen is the main fibrillar collagen in the interstitial extracellular matrix (ECM). In cancer development, perlecan and type IV collagen have multifunctional roles and when degraded from the BM, bioactive substances and other fragments are released in the circulation. Significant ECM changes also occur that lead to an accumulation of fibrillar collagens. Given their abundance in the ECM; perlecan, type IV and type I collagen are of interest for breast cancer progression and may be of importance as new biomarkers to monitor disease, predict patient outcome and the treatment effect.Aim: In this thesis, the protein and mRNA expression of perlecan, type IV and I collagen in breast cancer tissue is studied. The aim is to characterize the expression pattern of these proteins in breast cancer tissue and to see whether there is a correlation to known prognostic biomarkers and to the patient prognosis. Moreover, to evaluate circulating perlecan and type IV collagen as diagnostic and prognostic biomarkers in breast cancer patients.Methods: In this thesis project, eight different patient cohorts were used. In freshly frozen normal breast and breast cancer tissue, perlecan protein expression was visualized using immunofluorescence. Type IV and I collagen protein expression were studied with immunohistochemistry in formalin-fixed, paraffin embedded primary breast cancer tissue, and type IV collagen in metastatic breast cancer tissue. For gene expression analysis, mRNA and clinicopathological data were extracted from the Cancer Genome Atlas and cBioportal database. Circulating plasma levels of perlecan were analysed in breast cancer patients and controls, circulating levels of CA15-3 and type IV collagen in patients with primary and metastatic breast cancer as well as controls. Perlecan and type IV collagen were measured with ELISA assays, and CA15-3 were using an electrochemiluminescence immunoassay.Results: In breast cancer tissue, perlecan and type IV collagen protein expression in the epithelial BM was fragmented or completely lost, and perlecan and type IV collagen was expressed to varying extent in the tumour stroma. The mRNA analysis confirmed that type IV collagen mRNA was expressed in primary breast cancer tissue and highly expressed in metastatic tissue. Type I collagen was mostly highly expressed in the tumour stroma. Low type I collagen protein and mRNA expression correlated with biomarkers for aggressive breast cancer, but no effect on survival could be seen. Among patients receiving chemotherapy, low stromal type I collagen protein expression was associated with better survival compared to high expression, even after adjusting for other relevant factors. There was no correlation of perlecan or type IV collagen protein expression to clinically used prognostic biomarkers, but an oestrogen receptor dependent correlation between mRNA expression of perlecan and several matrix-degrading enzymes were found. Survival analysis showed that high stromal type IV collagen protein and mRNA expression in the primary tumour was significantly associated with a poorer survival, and high protein expression with a risk of developing distant metastasis. Metastatic breast cancer patients had higher levels of circulating type IV collagen compared to healthy controls and patients with primary breast cancer. High circulating type IV collagen levels correlated with poorer survival in metastatic breast cancer patients, and was superior to CA15-3 at detecting metastatic breast cancer.Conclusions: The protein expression pattern of perlecan, type IV collagen and type I collagen become abnormal during breast cancer development. Stromal type IV collagen protein and mRNA in the primary tumour correlates to poorer prognosis, most likely due to a higher risk of developing metastatic disease. Circulating type IV collagen can function as a biomarker for detecting metastatic disease in patients with primary breast cancer and is prognostic in patients with metastatic breast cancer. Low stromal type I collagen is a marker for an aggressive breast cancer disease and can predict chemotherapy response.
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| 2. |
- Bayadsi, Haytham, 1987-
(författare)
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Tumour stromal and demographical factors affecting the metastatic aggressiveness of small differentiated papillary thyroid cancers in Sweden
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The incidence of papillary thyroid cancer (PTC) has been increasing over the recent decades, especially that of small papillary thyroid cancers (sPTCs) (≤ 20mm in size). sPTCs are generally classified as low risk cancers with a very favourable diagnosis, yet some of these cancers still cause locoregional and distant metastasis, recurrence and even death.Aims: To investigate the role of tumour stromal, environmental and demographical factors affecting the metastatic aggressiveness of sPTCs in Sweden.Material & Methods: Selected tumour stromal proteins (Types I (Col1) and IV (Col4) collagens, alpha smooth muscle actin (a-SMA) and matrix metallopeptidase 9 (MMP-9)) were analysed for their role in metastatic disease (Paper I). Demographic and clinicopathological differences regarding recurrence between metastasized vs. non-metastasized sPTCs in Sweden were studied in 2 registry-based retrospective observational cohort studies (Papers II & III). The geographic distribution of patients with sPTC in Sweden was pinpointed and layered with maps of gamma radiation deposits of radionuclides Caesium-137 (Cs-137), Thorium-232 (Th-232), Uranium-238 (U-238) and Potassium-40 (K-40) using different spatial analysis methods (Paper IV).Results: Col1 and Col4 were significantly more expressed in the non-metastatic tumours compared with metastatic ones. Patients with N1b disease were younger, had a smaller tumour size and higher recurrence rates compared to patients with N0 and N1a disease. The mean number of metastatic LNs at initial surgery was higher in the N1b group than the N1a group and correlated with more recurrent disease. The prevalence of metastatic sPTC was associated with significantly higher levels of gamma radiation from Th-232, U-238 and K-40.Conclusions: The higher expression of Col1 and Col4 in the non-metastasized tumours indicates a potential protective role in tumour progression. LN stage N1b at diagnosis, and having five or more metastatic nodes, are strong risk factors for cancer recurrence and decreased disease-free survival in sPTC. Environmental factors such as gamma radiation are believed to play a major role in the pathogenesis of the PTC. These findings altogether underscore the importance of LN evaluation, tumour biological as well as environmental factors in sPTC patients, suggesting that the management of these patients should be based on an individual risk stratification instead of a “one size fits all” approach.
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| 3. |
- Bendrik, Christina, 1964-
(författare)
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Angiogenesis regulation in hormone dependent breast- and ovarian cancer
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Angiogenesis is a key event in tumor progression and a rate-limiting step in the establishment of a clinical cancer disease. The net balance of pro- and anti-angiogenesis mediators in the tissue dictates the angiogenic phenotype of a tumor. Matrix metalloproteinases (MMPs) are major regulators of extracellular matrix turnover and have for long been associated with pro-tumorigenic activities due to their tissue degradation capacities. However, broad-spectra MMP inhibitors as anti-tumor therapy in clinical trials have failed, and it has now become evident that several MMPs may induce biological activities beneficial to the host, such as suppressed angiogenesis. In this thesis the protective role of specific MMPs in breast and ovarian tumor tissues was further demonstrated.The process of angiogenesis is essential for physiological functions in the female reproductive tract, where sex steroids regulate new blood vessel formation and regression in each cycle. Despite progress made during the past years, our knowledge in sex steroid regulation of angiogenesis in hormone-dependent tumor tissues remains limited. Tamoxifen is a cornerstone in the treatment of estrogen receptor (ER)-positive breast cancer. The therapeutic value of tamoxifen in the treatment of ER-positive ovarian cancer is to date less investigated. The results presented in this thesis suggest that tamoxifen may induce anti-tumorigenic responses in ER-positive ovarian cancer by means of both anti-proliferative and anti-angiogenic mechanisms. In experimental models of human ovarian cancer in vitro and in vivo, tamoxifen treatment increased extracellular levels of MMP-9 and enhanced generation of the angiogenesis inhibitor endostatin which resulted in significantly decreased angiogenesis and tumor growth. Low levels of MMP-9 and endostatin in ascites collected from ovarian cancer patients suggest a possibility to therapeutically enhance MMP-9 by administration of tamoxifen, and thereby counteract angiogenesis in ovarian tumors by increased generation of anti-angiogenesis fragments, such as endostatin.The significance of enhanced MMP activities in tumor tissues was further investigated by experimental models of intratumoral MMP gene transfer to human breast tumor xenografts, which were assessed by using microdialysis. Treatment of tumors with MMP-9 or MMP-3 resulted in dose-dependent inhibition of tumor growth. Low dose of either MMP induced tumor stasis whereas a higher dose induced significant tumor regression. MMP-9 and tamoxifen exerted synergistic therapeutic effects on breast tumor angiogenesis and growth whereas gene transfer of the MMP-inhibitor TIMP-1 counteracted the beneficial effects induced by tamoxifen.Further on, we confirm the pro-angiogenic potential of estradiol by demonstrating a significant correlation between local levels of estradiol and the pro-angiogenic cytokine IL-8 in normal human breast tissues and in ER/PgR-positive breast cancers of women. Estradiol-induced IL-8 secretion was additionally confirmed in normal human whole breast biopsies in culture and in experimental human breast cancer in vitro and in vivo.In conclusion, the results of this thesis may hopefully increase the overall understanding of several mechanisms involved in angiogenesis regulation and may additionally be useful in the development of novel approaches for targeted therapy in the treatment of hormone-sensitive breast- and ovarian cancer.
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| 4. |
- Borgmästars, Emmy, 1990-
(författare)
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In search of early biomarkers in pancreatic ductal adenocarcinoma using multi-omics and bioinformatics
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive malignancy with a 5-year survival of 10 %. Surgery is the only curative treatment. Unfortunately, few patients are eligible for surgery due to late detection. Thus, we need ways to detect the disease at an earlier stage and for that good screening biomarkers could be used. Previous studies have analyzed circulating analytes in prospective studies to identify early PDAC signals. One such class is microRNAs (miRNAs). MicroRNAs are non-coding RNAs of around 22 nucleotides that act as post- transcriptional regulators by interaction with messenger RNAs (mRNAs). The function of a miRNA can be elucidated by target prediction, to identify its potential targets, followed by enrichment analysis of the predicted targets. Challenges with this approach includes a lot of false positives being generated and that miRNAs can perform their role in a tissue- or disease-specific manner. Other classes of analytes that have previously been studied in prospective PDAC cohorts are metabolites and proteins. Aims: This thesis has three aims. First, to build a miRNA functional analysis pipeline with correlation support between miRNA and its predicted target genes. Second, to identify potential circulating biomarkers for early detection of PDAC using multi-omics. Third, to identify potential prognostic metabolites in a prospective PDAC cohort.Methods: We used publicly available data from the cancer genome atlas-pancreatic adenocarcinoma (TCGA-PAAD) and pre-diagnostic plasma samples from the Northern Sweden Health and Disease Study. We built a pipeline in R including miRNA, mRNA, and protein expression data from TCGA-PAAD for in silico miRNA functional analysis. Pre- diagnostic plasma samples from future PDAC patients as well as matched healthy controls were analyzed using multi- omics. Tissue polypeptide specific antigen (TPS) was analyzed by enzyme linked immunosorbent assay in 267 future PDAC samples and 320 healthy controls. Metabolomics and clinical biomarkers (carbohydrate antigen (CA) 19-9, carcinoembryonic antigen (CEA), and CA 15-3) were profiled in 100 future PDAC samples and 100 healthy controls using liquid chromatography-mass spectrometry (MS), gas chromatography-MS, and multi-plex technology. Of these, a subset of 39 future PDAC patients and 39 healthy controls were profiled for 2083 microRNAs using targeted sequencing and 644 proteins using proximity extension assays. Circulating levels of multi-omics analytes were analyzed using conditional or unconditional logistic regression. Least absolute shrinkage and selection operator (LASSO) in combination with 500 bootstrap iterations identified the most informative variables. The prognostic value of metabolites was assessed using cox regression. Multi-omics factor analysis (MOFA) and data integration analysis for biomarker discovery using latent components (DIABLO) were used for multi-omics integration analyses.Results: An automated pipeline was built consisting of 1) miRNA target prediction, 2) correlation analyses between miRNA and its targets on mRNA and protein expression levels, and 3) functional enrichment of correlated targets to identify enriched Kyoto encyclopedia of genes and genomes (KEGG) pathways and gene ontology (GO) terms for a specific miRNA. The pipeline was run for all microRNAs (~700) detected in the TCGA-PAAD cohort. These results can be downloaded from a shiny app (https://emmbor.shinyapps.io/mirfa/). TPS was not altered in pre-diagnostic PDAC patients up to 24 years prior to diagnosis, but increased at diagnosis (OR = 1.03, 95 % CI: 1.01-1.05). Internal area under curves of 0.74, 0.80, and 0.88 were achieved for five metabolites, two proteins, and two miRNAs that were selected by LASSO and bootstrap iterations, in combination with CA 19-9. Neither MOFA nor DIABLO separated well between future PDAC cases and healthy controls. Conclusions: Our bioinformatics pipeline for in silico functional analysis of microRNAs successfully identifies enriched KEGG pathways and GO terms for miRNA isoforms. The investigated plasma samples are heterogeneous, but among the analyzed variables, we identified five metabolites, two proteins, and two microRNAs with highest potential for early PDAC detection. CA 19-9 levels increased closer to diagnosis. We identified five fatty acids that could be studied in a diagnostic PDAC cohort as prognostic biomarkers.
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| 5. |
- Bostner, Josefine, 1981-
(författare)
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The Akt/mTOR Pathway and Estrogen Receptor Phosphorylations : a crosstalk with potential to predict tamoxifen resistance in breast cancer
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Estrogen receptor α content is the primary breast cancer biomarker distinguishing the patients responsive from the non-responsive to endocrine treatments. Tamoxifen is an estrogen competitor with large potential to treat breast cancer patients and prolongs time to recurrence. Despite the estrogen receptor positivity and tamoxifen treatment, many women face recurrence of the disease. An important mechanism of resistance to endocrine treatments is upregulated growth factor signaling, and the subsequent effect on the estrogen receptor, rendering an active receptor that stimulates cell proliferation or reduced estrogen-receptor dependence.This thesis concerns the investigation of biomarkers, as a complement to the existing markers, for determining optimal treatment for patients with primary invasive breast cancer. Randomized patient tumor materials were used in order to measure variations in gene copies, proteins, and protein phosphorylations and to further relate these variations to time-to-recurrence. Endocrine untreated groups within the patient tumor sets gave us the opportunity to study the prognostic potential of selected markers and to compare tamoxifen-treated patients with endocrine untreated, thus obtaining a treatment-predictive value of each marker or marker combination.In endocrine-dependent cancer the 11q13 chromosomal region is frequently amplified, harboring the genes encoding the cell cycle stimulator cyclin D1 and the estrogen receptor phosphorylating kinase Pak1, respectively. Amplification of the genes was associated with reduced time-torecurrence, indicating a prognostic value, whereas PAK1 gene amplification predicted reduced response to tamoxifen treatment. Moreover, the protein expression of Pak1 tended to predict treatment response, which led to the investigation of this protein in a larger cohort. Together with one of its targets, the estrogen receptor phosphorylation at serine 305, Pak1 predicted reduced response to tamoxifen treatment when detected in the nucleus of tumor cells, suggesting activation of this pathway as a mechanism for tamoxifen-treatment resistance. The estrogen receptor is phosphorylated by several growth factor stimulated kinases. The role of serine-167 phosphorylation has been debated, with inconsistent results. To study the biomarker value of this site the upstream activity of Akt, mTOR, and the S6 kinases were analyzed individually and in combinations. As a prognostic factor, serine 167 indicated an improved breast cancer survival, and as a treatment predictive factor we could not detect a significant value of serine 167 as a single marker. However, in combination with serine 305, and Akt/mTOR-pathway activation, the response to tamoxifen treatment was reduced. The mTOR effector protein S6K1 was found to be associated with HER2 positivity and a worse prognosis. In the group of patients with S6K1 accumulation in the tumor cell nuclei, treatment did not prolong time-to-recurrence, similarly as observed with expression of active S6 kinases. In vitro, a simultaneous knockdown of the S6 kinases in estrogen receptor-positive breast cancer cells resulted in G1 arrest, and tamoxifen-induced G1 arrest was in part S6 kinase dependent.The results presented herein suggest biomarkers that would improve treatment decisions in the clinic, specifically for estrogen receptor-positive breast cancer and tamoxifen treatment but in a broader perspective, also for other endocrine treatments and targeted treatments.
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| 6. |
- Edfeldt, Katarina, 1979-
(författare)
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Small Intestinal Neuroendocrine Tumours : Genetic and Epigenetic Studies and Novel Serum Biomarkers
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small intestinal neuroendocrine tumours (SI-NETs) are rare, hormone producing and proliferate slowly. Patients usually display metastases at time of diagnosis, the tumours are difficult to cure, and the disease course is unpredictable.The gene expression pattern was investigated in paper I, with emphasis on aggressive disease and tumour progression. Expression microarrays were performed on 42 tumours. Unsupervised hierarchal clustering revealed three clusters that were correlated to clinical features, and expression changes from primary tumour to metastasis. Eight novel genes, ACTG2, GREM2, REG3A, TUSC2, RUNX1, TGFBR2, TPH1 and CDH6 may be of importance for tumour progression.In paper II, expression of ACTG2 was detected in a fraction of SI-NETs, but not in normal enterochromaffin cells. Inhibition of histone methyltransferase and transfection of miR-145 induced expression and no effect was seen after DNA methylation or selective EZH2 inhibition in vitro. miR-145 expression was reduced in metastases compared to primary tumours. Overexpression of ACTG2 inhibited cell growth, and inducing ACTG2 may have therapeutic effects.TCEB3C (Elongin A3) is located on chromosome 18 and is imprinted in some tissues. In paper III a reduced protein expression was detected. The gene was epigenetically repressed by both DNA and histone methylation in a tumour tissue specific context. The expression was also induced in primary cell cultures after DNA demethylation and pyrosequencing revealed promoter region hypermethylation. Overexpression of TCEB3C inhibited cell growth by 50%, suggesting TCEB3C to be a tumour suppressor gene.In paper IV, 69 biomarkers were analysed in blood serum using multiplex proximity ligation assay. Nineteen markers displayed different levels between patients and controls. In an extended cohort, ELISA analysis showed elevated serum levels of Mindin, DcR3 and TFF3 in patients and protein expression in tumour cells. High levels of DcR3 and TFF3 were associated with poor survival, and DcR3 may be a marker for liver metastases. Mindin, DcR3, and TFF3 are potential novel diagnostic biomarkers for SI-NETs.
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| 7. |
- Franklin, Oskar, 1985-
(författare)
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Stromal components and micro-RNAs as biomarkers in pancreatic cancer
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Pancreatic ductal adenocarcinoma (PDAC) patients have the poorest 5-year survival rates of all cancer forms. It is difficult to diagnose at early disease stages, tumour relapse after surgery is common, and current chemotherapies are ineffective. Carbohydrate antigen 19-9 (Ca 19-9), the only clinically implemented PDAC biomarker, is insufficient for diagnostic and screening purposes.PDAC tumours are characterised by a voluminous stroma that is rich in extracellular matrix (ECM) molecules such as collagens, hyaluronan (HA) and matricellular proteins. These stromal components have been suggested to promote PDAC cell migration, proliferation, evasion of apoptosis and chemotherapy resistance. Those events are mediated via interactions with adhesion receptors, such as integrins and CD44 receptors expressed on cancer cell surfaces.Micro-RNAs (miRNA) post-transcriptionally regulate gene expression in health and disease. At the time of PDAC diagnosis, miRNA levels are altered both in plasma and tumour tissue. Before PDAC diagnosis, tissue miRNA levels are altered in precursor lesions, raising the possibility that plasma miRNAs might aid in early detection.In this thesis, it is hypothesised that stromal components and miRNAs can serve as tissue or blood based biomarkers in PDAC. The aims are: (1) to characterise the expression of stromal components and their receptors in normal and cancerous tissue; (2) to find potential stroma-associated tissue and blood-based biomarkers for diagnosis and prognosis estimates; (3) to determine the cellular effects of type IV collagen (Col IV) in PDAC; (4) to determine if plasma miRNAs that are altered in manifest PDAC can be used to diagnose PDAC earlier.Methods The expression patterns of Col IV, Col IV-binding integrin subunits (α1, α2, β1), Endostatin, Osteopontin (OPN) and Tenascin C (TNC) were analysed in frozen PDAC and normal pancreatic tissue. A tissue microarray (TMA) was constructed using formalin-fixed, paraffin-embedded primary tumours and lymph node metastases. The TMA was used to study the expression levels and associations with survival of the standard CD44 receptor (CD44s), its variant isoform 6 (CD44v6), HA, OPN and Col IV. Circulating levels of HA, Col IV, Endostatin, OPN and TNC were measured in PDAC patients and healthy individuals, and compared with conventional tumour markers (Ca 19-9, CEA, Ca 125 and TPS). The functional roles of Col IV were studied in PDAC cell lines by: (1) growth on different matrices (2) blocking Col IV binding integrin subunits, (3) blocking the Col IV domains 7s, CB3 and NC1, and (4) by down regulation of PDAC cell synthesis of Col IV using siRNA transfection. Plasma miRNAs alterations were screened for in samples from patients with manifest disease, using real-time quantitative PCR (RT-qPCR). To find early miRNA alterations, levels of those miRNAs that were altered at diagnosis were measured in prediagnostic plasma samples.Results High tissue expression of both the standard CD44 receptor (CD44s) and its variant isoform CD44v6 as well as low expression of stromal OPN were associated with poor survival. In addition, high CD44s and low OPN predicted poor survival independent of established prognostic factors.Circulating Col IV, Endostatin, OPN, TNC and HA were increased in preoperative samples from PDAC patients. Preoperatively, higher levels of serum-HA and plasma-Endostatin were associated with shorter survival. Postoperatively, higher levels of Col IV, Endostatin and OPN were associated with shorter survival. On the contrary, only one of the conventional tumour markers was associated with survival (Ca 125).Col IV stimulated PDAC cell proliferation and migration and inhibited apoptosis in vitro, dependent on the collagenous domain (CB3) of Col IV and the Col IV binding integrin subunit β1. Reduced endogenous Col IV synthesis inhibited these effects, suggesting that PDAC cells synthesise Col IV to stimulate tumour-promoting events via a newly discovered autocrine loop.15 miRNAs were altered in early stage PDAC patients and the combination of these markers outperformed Ca 19-9 in discriminating patients from healthy individuals. However, none of the miRNAs were altered in prediagnostic samples, suggesting that plasma miRNA alterations appear late in the disease course.Conclusions Up regulated stromal components in PDAC tumours are detectable in blood samples and are potential diagnostic and prognostic biomarkers in PDAC. High circulating levels of Col IV, Endostatin, OPN and HA predict poor survival, as well as high expression of CD44s and CD44v6 and low expression of OPN in tumour tissue. PDAC cells synthesise Col IV, which forms BM-like structures close to cancer cells and promote tumour progression in vitro via an autocrine loop. Several plasma-miRNAs are altered in PDAC, but are not useful for early discovery.
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| 8. |
- Grahn, Oskar, 1985-
(författare)
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Modulating the inflammatory response after colorectal cancer surgery : friend or foe?
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer was the second most deadly and third most common cancer globally in 2020. In Sweden, more than 5,000 new colonic cancer cases and more than 2,000 rectalcancer cases were reported in 2021, making colorectal cancer the third most common in Sweden (excluding skin malignancies).Anastomotic leakage after colorectal cancer surgery is a feared complication that confers substantial morbidity, including a higher risk of permanent stoma and cardiovascular morbidity, but can also impart an increased risk of recurrence and mortality; the reason why leakage might cause this is not established. Perioperative inflammation including upregulation of cyclooxygenase-enzymes, which is further increased by anastomotic leakage, can possibly modulate both anastomotic healing as well as impact minimal residual disease. Non-steroidal anti-inflammatory drugs (NSAIDs) act by inhibiting COX-enzymes and can be part of a postoperative multimodal analgesia protocol. However, their postoperative use has been debated, with fears of NSAIDs possibly increasing anastomotic leakage rates.Study I was a retrospective cohort study on 1,341 patients who had undergone anterior resection for rectal cancer. Exposure was at least two days with NSAIDs during the first postoperative week, and the primary outcome was recurrence-free survival. A Cox regression model could not demonstrate a significant association with a hazard ratio (HR) of 1.02 (95% confidence interval (CI): 0.79–1.33) and neither did a propensity score-matched analysis. An instrumental variable analysis displayed a tentative improvement in recurrence-free survival in the NSAID-exposed (HR 0.61; 95% CI 0.38–0.99), but the core assumptions to perform such an analysis were not fully satisfied.Study II was a protocol-based retrospective cohort study with a total of 6,945 patients resected for colorectal cancer with a primary anastomosis formed. NSAID-exposure was determined by each individual hospital’s postoperative analgesia protocol, while patient data and outcomes were retrieved from the Swedish colorectal cancer registry. Some 3,996 (58%) patients were treated at a hospital with NSAIDs included in their postoperative analgesia protocol. No significant association with recurrence-free survival was seen (HR 0.97, 95% CI0.87–1.09). However, a reduction in cancer recurrence was demonstrated (HR 0.83, 95% CI0.72‒0.95), with an increased risk reduction for locoregional (HR 0.68, 95% CI 0.48–0.97) in comparison to distant recurrence (HR 0.85, 95% CI 0.74–0.98). Anastomotic leakage was less frequent as well, mainly because of a reduction in the group with colorectal or ileorectal anastomoses (HR 0.47, 95% CI 0.33–0.68).In Study III, the aim was to explore proteomic and biological pathway alterations in patients with peritoneal infection. This was a 1:1 matched cohort study on patients resected for colorectal cancer with a primary anastomosis formed, including 32 cases who suffered a postoperative peritoneal infection matched with 32 controls with a complication-free postoperative stay. Serum samples were retrieved from their first postoperative visit and at one year postoperatively. Out of a total of 270 proteins tested, 77 were differentially expressed at the first postoperative visit at a median sampling time of 41 days after surgery. Many of the top hub proteins are known actors in colorectal cancer progression, including survival and invasiveness, potentially enhancing minimal residual disease. Over-represented pathways were related to cardiomyopathy, cell-adhesion, extracellular matrix, phosphatidylinositol-3-kinase/Akt (PI3K-Akt) and transforming growth factor beta (TGF-Beta) signalling.In Study IV, the aim was to evaluate the frequency of a known polymorphism of the COX-2 gene promotor -765G>C in a Swedish cohort of colorectal cancer patients, and whether a previously reported association between this gene variant with an increase in anastomotic leakage could be reproduced. This was a 1:1 matched case-control study on a total of 94 patients who were resected for colorectal cancer with a subsequent primary anastomosis, with cases suffering a peritoneal infection. Preoperative blood and serum samples were genotyped and analysed using pre-defined protein panels. Of the 94 patients in total, one in each group were homozygous for the minor allele C/C, and ten cases and 14 controls were heterozygous with G/C and the rest were homozygous for the major allele. Thus, there were fewer individuals with the minor allele in the case group, with a non-significant odds ratio of 0.71(p=0.413), ultimately not replicating the finding of the previous study. The protein quantitative trait loci analysis rendered no associations of interest.In conclusion, no statistically significant effects on recurrence-free survival from postoperative NSAIDs in patients resected for colorectal cancer could be demonstrated in study I, whereas significant associations between NSAID use and reduction in frequency of anastomotic leaks as well as cancer recurrence could be shown in study II. In study III, numerous proteins were differentially expressed in patients suffering a postoperative peritoneal infection, even after more than a month’s duration, potentially stimulating minimal residual disease. The over-representation analysis found pathways related to cardiomyopathy, which could help explain the increase in cardiovascular morbidity in patients suffering anastomotic leakage. Study IV could not reproduce the potentially marked increase in anastomotic leak frequency in carriers of the COX-2 gene promotor -765G>C polymorphism in a Swedish sample. Whether to include NSAIDs or not in postoperative multimodal analgesia is a question still not answered, and it may depend on the genotype, the patient’s preoperative inflammatory state, tumour location, the specific NSAID used, and whether a leak has already occurred. NSAIDs might have effects on both morbidity including cardiovascular and anastomotic leakage as well as minimal residual disease including recurrence and mortality. This thesis suggests potential protective effects regarding both anastomotic leakage as well as cancer recurrence, but it seems to depend on at least some of the aforementioned factors. The proteomic landscape regarding postoperative peritoneal infection has been investigated, and where it has also been demonstrated that the duration of said alterations can be greater than was earlier suspected. Finally, even if a replication attempt was not successful considering the relation between a COX-2 gene promotor polymorphism and anastomotic leakage, it could be worthwhile to attempt further replication studies.
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| 9. |
- Holmgren, Klas, 1989-
(författare)
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Permanent stoma after anterior resection for rectal cancer : prevalence and mechanisms
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- While sphincter-saving surgery constitutes standard treatment for rectal cancer, anterior resection still harbours a significant risk of a permanent stoma in the long run. Although anastomotic leakage plays a major role in this surgical dilemma, the exact mechanisms are not known, while surveys indicate a stoma-free outcome is essential for a majority of patients. To address this issue, the overall aim of the present thesis was to investigate the permanent stoma prevalence in patients undergoing anterior resection for rectal cancer in Sweden, and to identify plausible mechanisms that impede prospects of a stoma-free outcome.In a population-based cohort, chart review of patients who had anterior resection for rectal cancer in the Northern healthcare region in Sweden between 2007 and 2013 showed that 75 out of 316 (24%) patients ended up with a permanent stoma. Of 274 patients (87%) primarily defunctioned with a stoma, 229 underwent stoma closure, 21 (9%) of whom suffered major complications that required return to theatre or worse. A permanent stoma was shown to be more common among patients with anastomotic leakage and an advanced tumour stage.A registry-based method to estimate nationwide stoma outcome after anterior resection for rectal cancer was developed, using data from the Swedish Colorectal Cancer Registry and the National Patient Registry. With a chart-reviewed cohort as reference, stoma outcome was assessed with a positive predictive value of 85.1%, and a negative predictive value of 100.0%. In patients operated in Sweden between 2007 and 2013, the registry-based method determined that 942 out of 4768 (19.8%) had a permanent stoma, while stoma rates varied substantially between different healthcare regions.In a 1:1 matched case-control study of 82 patients who had curative resection for non-disseminated colorectal cancer, a subgroup analysis of 34 patients with rectal cancer displayed biomarker aberrations in serum measured preoperatively in those with anastomotic leakage. Compared to complication-free controls, 15 proteins related to inflammation were elevated, of which two (C-X-C motif chemokine 6, and C-C motif chemokine 11) remained significant after adjustment for multiple testing.Based on a cohort of 4529 patients who had anterior resection, tumour height served as a proxy to determine the extent of mesorectal excision, while long-term stoma outcome was classified using a previously validated registry-based method. Defunctioning stomas significantly decreased chances of a stoma-free outcome, especially in patients undergoing partial mesorectal excision; for these patients, faecal diversion was also least beneficial in terms of reducing anastomotic leakage.In conclusion, every fifth patient undergoing anterior resection for rectal cancer in Sweden eventually ends up with a permanent stoma. Although construction of a defunctioning stoma decreases the risk of symptomatic anastomotic leakage, subsequent takedown surgery carries a substantial risk of major complications, while chances of a long-term stoma-free outcome become significantly reduced. To facilitate selective use of faecal diversion, novel markers to identify high-risk anastomoses prior to surgery have been identified, but require validation in larger prospective settings. Anterior resection without a defunctioning stoma should be considered in appropriately informed patients for whom a stoma-free outcome is of importance. In particular, this holds true for patients eligible for partial mesorectal excision, where anastomotic dehiscence is less frequent and the advantageous effects of a defunctioning stoma are limited.
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| 10. |
- Holsti, Mari, 1963-
(författare)
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Vascular remodelling and circulating basement membrane fragments in abdominal aortic aneurysm
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An abdominal aortic aneurysm (AAA) is a degenerative disease, characterized by advanced inflammation and extracellular matrix (ECM) remodelling. Enhanced protease activity mediated by cytokines results in the degradation of ECM proteins, leading to the generation of different bioactive fragments. Some of these generated fragments are released from the vascular basement membrane (VBM), a highly specialized ECM. VBM provides mechanical and structural stability and regulates many important cellular functions of the vascular system. Type IV and XVIII collagens are two structural proteins in VBM, with crucial roles in maintaining of the VBM integrity and vascular architecture. Circulating levels of type IV and XVIII collagen fragments are found physiologically, but have also been associated with many diseases. Remodelling of VBM and expression of its components has not been as well studied in AAA as that of the interstitial ECM.Here we investigate these VBM collagens, their expression and possible association with aortic diameter and expansion rate in individuals with an AAA in comparison with different control groups. Further we study whether there is a link between the circulating VBM collagen fragments and several inflammatory markers, all highly involved in AAA pathogenesis. Lastly, we study the impact of surgical intervention on plasma levels of VBM collagens in patients treated by either open surgical repair (OSR) or endovascular aortic aneurysm repair (EVAR).Methods: Circulating levels of type IV and XVIII collagen fragments were analysed in individuals with an AAA and compared with healthy controls and patients with peripheral artery disease (paper I). A possible association between VBM collagen fragments and the aortic diameter and expansion was studied in a large population-based cohort of 615 men stratified into three aortic diameter groups based on initial maximum aortic diameter (paper II). Furthermore, 159 individuals were followed up over time with repeated measurements of aortic diameter and blood samples. The follow up cohort were divided into two subgroups based on expansion rate of AAA. Moreover, the location of VBM collagens in tissue from aortic wall in individuals with an AAA was characterized and the expression pattern was compared with normal aorta (paper II). In paper III, the association between the plasma levels of VBM collagens and inflammatory markers; IL-1 (IL-1α and IL-1β), IL-6, IL-8, TNF-α INF-γ and hs-CRP were studied in same cohort as paper II. Finally, the effect of surgical intervention on circulating levels of VBM collagen fragments was investigated in AAA patients who had undegone either OSR or EVAR by comparison of plasma levels before and after AAA repair.Ultrasound technique was used for measurements of aortic diameter (paper I, II, III and IV). Analysis of circulating VBM collagens and inflammatory markers were performed by ELISA-assay (Paper I, II, III and IV) and Multiplex-assays, respectively (paper III). Aortic wall tissues were analysed by haematoxylin and eosin (H&E) and immunofluorescence staining (Paper II).Results: There were significantly increased plasma levels of VBM collagen fragments in individuals with an AAA, compared with healthy controls and individulas with a peripheral artery disease (PAD), (Paper I). The levels of type IV collagen in AAA patients did not differ from the group with PAD, and there were no significant differences between the control groups regarding plasma levels of both VBM collagen fragments (Paper I). The increased levels of VBM collagen fragments were significantly associated with aortic diameter with highest levels in the group with an AAA (Paper II). Altered expression of the VBM collagens and fragmentation of elastic fibres were observed in tissue from AAA patients (Paper II). A significant association between the levels of pro-inflammatory cytokines IL-6 and IL-8, and VBM collagens was found. Additionally, there were a significant association between the plasma levels of IL-8, TNF-α and hs-CRP and an AAA (Paper III). Aneurysms with faster expansion rate had significantly higher levels of IL-6, IL-1β, and type XVIII/endostatin collagen. Additionally, IL-6, type XVIII/endostatin collagen and baseline-aortic diameter were significantly associated with expansion rate (Paper III). AAA repair was associated with changes in plasma levels of VBM collagens (Paper IV).Conclusion: Circulating levels of VBM collagens were increased in patients with an AAA, and significantly associated with aortic diameter and expansion rate. The expression of VBM collagens was altered in AAA tissue compared with normal aorta. In addition, plasma levels of several inflammatory markers were associated as with VBM collagens, aortic diameter and expansion rate. The levels of both VBM collagens were altered at short and long time after AAA repair.
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