1. |
- Silins, Isabella, 1983-
(författare)
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Improved adrenocortical PET imaging
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Adrenal tumours can either be benign or malignant, hormone secreting or not, and they can be discovered through clinical examination of the patient or by pure chance. Increased knowledge in the area, plus the widespread use of imaging techniques, have resulted in a rising number of patients with adrenal tumours that subsequently need to be diagnosed. Improved imaging is needed for primary aldosteronism (PA) and adrenocortical carcinoma (ACC) but the positron emission tomography (PET) tracer currently in use, [11C]metomidate (MTO), has many important limitations. This thesis aims to improve adrenocortical PET imaging.Methods: Paper 1 investigated the pre-clinical properties of Para-Chloro-2-[18F]fluoroethyl-etomidate (CETO), by autoradiography, binding studies, ex vivo biodistribution on rats and in vivo imaging using mice and one non-human primate (NHP). Paper II investigated the clinical properties of [18F]CETO and included patients with various kinds of adrenocortical tumours, and healthy volunteers. Metabolic and kinetic analyses were performed and three out of five healthy volunteers also underwent [15O]water PET/CT to measure adrenal blood flow. Test-retest was performed on all healthy volunteers. Paper III assessed the in vivo and in-human radiation dosimetry of [18F]CETO. Ex vivo uptake data from rats and in vivo PET/CT from NHP and humans were used to calculate residence times. Paper IV evaluated the use of the block-sequential regularized expectation maximization (BSREM) reconstruction algorithm (Q.Clear, GE Healthcare, Milwaukee, USA) for [11C]MTO PET/CT in patients with PA.Results: Papers I and II demonstrated that [18F]CETO is highly specific to the adrenal cortex both in vitro and in vivo. The non-specific binding of [18F]CETO in the liver was significantly lower than that of [11C]MTO. [18F]CETO metabolizes rapidly and the single tissue irreversible (1T1k) kinetic model provided the best fit. [15O]water PET/CT results indicated that the adrenal [18F]CETO uptake was flow limited. Several retest values, including adrenal blood flow, were lower than the test values. Paper III found that the effective dose based on human data was 18.2 μSv/MBq and that the adrenal glands were the limiting organ regardless of species used. Paper IV showed that the BSREM reconstruction algorithm improves image quality, without compromising SUVmax quantification, and a β-value between 70 and 130 was found optimal.Conclusion: [18F]CETO PET/CT is a promising method for adrenocortical imaging and is safe for clinical imaging in terms of radiation dose. [18F]CETO PET/CT should be further investigated in patients with PA or ACC, preferably in conjunction with BSREM reconstruction.
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2. |
- Backman, Samuel, 1994-
(författare)
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Molecular studies of endocrine tumors : Insights from genetics and epigenetics
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endocrine tumors may be benign or malignant and may occur in any of the hormone producing tissues. They share several biological characteristics, including a low mutation-burden, and may co-occur in several hereditary tumor syndromes. The aim of this thesis was to identify genetic and epigenetic aberrations in endocrine tumors.In paper I we performed a comprehensive DNA methylation analysis of 39 pheochromocytomas/paragangliomas as well as 4 normal adrenal medullae on the HumanMethylation27 BeadChip array. We validated two previously described clusters based on DNA methylation with distinct genetic associations.In Paper II we performed a transcriptomic analysis of 15 aldosterone producing adenomas. CTNNB1-mutated tumors were found to form a distinct subgroup based on gene expression and to share gene expression similarities with non-aldosterone producing adrenocortical tumors with CTNNB1 mutations, including overexpression of AFF3 and ISM1.In paper III we used whole genome sequencing to identify germline genetic variants in 14 patients with Multiple Endocrine Neoplasia type 1 previously found to be wildtype for the MEN1 gene on routine clinical testing. Three patients were found to carry previously undetected MEN1 mutations. Two patients were confirmed to have phenocopies caused by variants affecting CASR or CDC73. In total 9/14 patients were not found to have a disease-causing germline variant, suggesting that the syndrome may in some cases be due to chance co-occurrence of several sporadic tumors.In paper IV RNA-Seq and whole genome sequencing of a cohort of SI-NETs selected on the basis of unusually short or long survival was performed in order to identify disease causing genes and potential prognostic factors. We confirmed known genetic aberrations and found rare variants in known cancer driver genes. Based on gene expression two clusters that differ in prognosis were detected. Moreover, through integration of copy number variation data and gene expression, we identied novel potential disease causing genes.
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3. |
- Barazeghi, Elham
(författare)
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Studies of epigenetic deregulation in parathyroid tumors and small intestinal neuroendocrine tumors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Deregulation of the epigenome is associated with the initiation and progression of various types of human cancers. Here we investigated the level of 5-hydroxymethylcytosine (5hmC), expression and function of TET1 and TET2, and DNA methylation in parathyroid tumors and small intestinal neuroendocrine tumors (SI-NETs).In Paper I, an undetectable/very low level of 5hmC in parathyroid carcinomas (PCs) compared to parathyroid adenomas with positive staining, suggested that 5hmC may represent a novel biomarker for parathyroid malignancy. Immunohistochemistry revealed that increased tumor weight in adenomas was associated with a more aberrant staining pattern of 5hmC and TET1. A growth regulatory role of TET1 was demonstrated in parathyroid tumor cells.Paper II revealed that the expression of TET2 was also deregulated in PCs, and promoter hypermethylation was detected in PCs when compared to normal parathyroid tissues. 5-aza-2′-deoxycytidine treatment of a primary PC cell culture induced TET2 expression and further supported involvement of promoter hypermethylation in TET2 gene repression. TET2 knockout demonstrated a role for TET2 in cell growth and migration, and as a candidate tumor suppressor gene.In Paper III, variable levels of 5hmC, and aberrant expression of TET1 and TET2 were observed in SI-NETs. We demonstrated a growth regulatory role for TET1, and cytoplasmic expression with absent nuclear localization for TET2 in SI-NETs. In vitro experiments supported the involvement of exportin-1 in TET2 mislocalization, and suggested that KPT-330/selinexor, an orally bioavailable selective inhibitor of exportin-1 and nuclear export, with anti-cancer effects, could be further investigated as a therapeutic option in patients with SI-NETs.In Paper IV, DNA methylation was compared between SI-NET primary tumors and metastases by reduced representation bisulfite sequencing. Three differentially methylated regions (DMR) on chromosome 18 were detected and chosen for further analyses. The PTPRM gene, at 18p11, displayed low expression in SI-NETs with high levels of methylation in the presumed CpG island shores, and in the DMR rather than the promoter region or exon 1/intron 1 boundary. PTPRM overexpression resulted in inhibition of cell growth, proliferation, and induction of apoptosis in SI-NET cells, suggesting a role for PTPRM as an epigenetically deregulated candidate tumor suppressor gene in SI-NETs.
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4. |
- Daskalakis, Kosmas
(författare)
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Small Intestinal Neuroendocrine Tumors : Clinical Studies, Novel Serum Biomarkers and Sensitivity to Cytotoxic and Targeted Agents
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small Intestinal Neuroendocrine Tumors (SI-NETs) are indolent neoplasms with an increasing annual incidence of approximately 1/100 000 people. They are often diagnosed at a late stage, restricting treatment efficacy. The aim of this thesis was to investigate clinical aspects of patients with advanced and/or disseminated disease with regard to clinical signs and management of abdominal fibrosis, the role of locoregional surgery and liver transplantation, as well as the ex vivo sensitivity of tumor samples to cytotoxic and targeted agents. Additionally, novel serum biomarkers for the diagnosis and prognosis of SI-NETs were investigated. In Paper I, abdominal fibrosis induced by serotonin and other cytokines from tumor cells, was associated with clinically significant symptoms of intestinal ischemia and/or obstructive uropathy, and was linked to advanced disease. Prompt recognition and minimally invasive intervention with superior mesenteric vein stenting and/or percutaneous nephrostomy and J stent treatment were effective in disease palliation. Paper II challenged the role of prophylactic, upfront locoregional surgery in Stage IV, which conferred no survival advantage in asymptomatic SI-NET patients. The option of delayed surgery as needed seemed to be comparable in all the outcomes examined, whilst also offering the advantage of fewer re-operations for intestinal obstruction in patients with already disseminated disease. Paper III confirmed that most young patients (<65 years) with SI-NET and liver metastases had a favorable survival with standardized multimodality treatment and that survival figures reported after liver transplantation for NETs do not surpass these figures. In Paper IV, 145 biomarkers were analyzed in blood serum using two different multiplex proximity assays. Subsequent ELISA and immunohistochemical analyses identified DcR3, TFF3 and midkine as novel serum biomarkers for SI-NETs. In Paper V, SI-NET samples were profiled with respect to sensitivity ex vivo to a panel of standard chemotherapeutics and targeted agents using a short-term total cell kill assay. SI-NETs exhibited variable but generally intermediate sensitivity ex vivo compared with other cancer diagnoses, calling for individualized selection of therapy.
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5. |
- Delgado Verdugo, Alberto
(författare)
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Genetic Aspects of Endocrine Tumorigenesis : A Hunt for the Endocrine Neoplasia Gene
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endocrine tumors arise from endocrine glands. Most endocrine tumors are benign but malignant variants exist. Several endocrine neoplasms display loss of parts of chromosome 11 or 18, produce hormones and responds poorly to conventional chemotherapeutics. The multiple endocrine neoplasia syndromes are mainly confined to endocrine tumors. This opens the question if there exists a single or several endocrine tumor genes.The aim of the study was to describe genetic derangements in endocrine tumors.Paper I: Investigation of mutational status of SDHAF2 in parathyroid tumors. SDHAF2 is located in the proximity of 11q13, a region that frequently displays loss in parathyroid tumors. We established that mutations in SDHAF2 are infrequent in parathyroid tumors.Paper II: Study of SDHAF2 gene expression in a cohort of benign pheochromocytomas (PCC) (n=40) and malignant PCC (n=10). We discovered a subset of benign PCC (28/40) and all malignant PCC (10/10) with significantly lower SDHAF2 expression. Benign PCC with low SDHAF2 expression and malignant tumors consistently expressing low levels of SDHAF2 were methylated in the promoter region. SDHAF2 expression was restored in vitro after treatment with 5- aza-2-deoxycytidine.Paper III: HumanMethylation27 array (Illumina) covering 27578 CpG sites spanning over 14495 genes were analyzed in a discovery cohort of 10 primary small neuroendocrine tumors (SI-NETs) with matched metastases. 2697 genes showed different methylation pattern between the primary tumor and its metastasis. We identified several hypermethylated genes in key regions. Unsupervised clustering of the tumors identified three distinct clusters, one with a highly malignant behavior.Paper IV: Loss of chromosome 18 is the most frequent genetic aberration in SI-NETs. DNA from SI-NETs were subjected to whole exome capture sequencing and high resolution SNP array. Genomic profiling revealed loss of chromosome 18 in 5 out of 7 SI-NETs. No tumor-specific somatic mutation on chromosome 18 was identified which suggests involvement of other mechanisms than point mutations in SI-NET tumorigenesis.Paper V: The cost for diagnostic genetic screening of common susceptibility genes in PCC is expensive and labor intensive. Three PCC from three patients with no known family history were chosen for exome capture sequencing. We identified three variants in known candidate genes. We suggest that exome-capture sequencing is a quick and cost-effective tool.
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6. |
- Langerth, Ann
(författare)
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Endoscopic retrograde cholangiopancreatography : Perforation and long-term outcomes after endoscopic sphincterotomy
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endoscopic retrograde cholangio pancreatography (ERCP) is a commonly used procedure in various disorders of the pancreatobiliary tract. When extracting common bile duct stones (CBDS), the major duodenal papilla is divided using a papillotome to perform an endoscopic sphincterotomy (ES). Adverse events occurring shortly after ES are well-known and include perforation which, however, is difficult to investigate due to its low frequency. ES is often used in elderly and/or infirm patients with gallstone pancreatitis and cholangitis, to prevent relapse in biliary events linked to CBDS. Subsequent cholecystectomy in these patients remains controversial. What happens in the long term after ES is still partially unknown.In Paper I, we found an increased risk for both cholangitis and pancreatitis after ES for CBDS, without synchronic relapse of CBDS and when compared with the general population was found. In Paper II, we retained the ES group, but replaced the control group with controls with a history of gallstone disease. The increased risk for both cholangitis and pancreatitis without relapse of CBDS still remains but, no higher risk for malignancy in the pancreatobiliary tract was noted.We conducted study III, a prospective follow-up after ES, to evaluate to what extent ES prevents relapse into biliary events after cholangitis and pancreatitis caused by bile duct stones. We included 100 patients who did not have earlier gallbladder surgery and who were treated for pancreatitis and/or cholangitis. The patients then underwent ES but not cholecystectomy and were followed for a mean of 42 months. None of the patients had recurrent pancreatitis and one had cholangitis. This indicates that ES alone is an alternative to cholecystectomy in the prevention of further attacks of acute pancreatitis and cholangitis.Paper IV consists of 52,140 ERCPs that were registered with GallRiks, a Swedish population based register. A total of 376 cases were registered as perforations and 75 patients had a fatal outcome. These data showed that sphincterotomy in the pancreatic duct increased the risk of death from perforation but the risk of death was reduced when ERCP was performed at a Q4 centre.
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7. |
- Norlén, Olov
(författare)
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Small Intestinal Neuroendocrine Tumor : A Rare Malignancy with Favorable Outcome
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small intestinal neuroendocrine tumor (SI-NET) is the most common small bowel tumor in Europe and USA, with an annual incidence of around 0.3-1.3/100000 persons. SI-NETs are the most common type of gastroenteropancreatic NETs (GEP-NETs), and they are known for their ability to produce hormones such as tachykinins and serotonin, as well as for their favorable long-term prognosis in comparison to gastrointestinal adenocarcinoma. The overall aim of the thesis was to investigate unknown or unclear aspects of SI-NET disease, in connection with prognosis, treatment and follow-up. Paper I confirmed several known negative prognostic factors and also showed, for the first time, that para-aortal lymph node metastases and peritoneal carcinomatosis were associated with worse survival by multivariable analyses. Locoregional surgery was associated with a low post-operative mortality, and a prolonged long-term survival by multivariable analysis. In Paper II we continued to investigate peritoneal carcinomatosis and found it be a risk factor not only for death, but also for emergency re-surgery. Furthermore, genetic analyses of samples from primary tumors in patients with and without peritoneal carcinomatosis showed a difference in the DNA between these two groups. In Paper III the outcome after liver surgery and/or radiofrequency ablation of liver metastases was investigated. To summarize, no difference in survival was seen in patients treated with surgery/radiofrequency ablation in comparison with matched controls. However, a superior radiological response of liver metasases and lower U-5-HIAA values were seen in patients subjected to liver surgery and/or radiofrequency ablation compared to matched controls. Paper IV compared ultrasonography, computed tomography and 11C-5HTP-PET in the follow-up after radiofrequency ablation of NET liver metastases. The study concluded that 11C-5HTP-PET depicted all residual tumors after RFA and that it, if used, should be combined with computed tomography for easier interpretation, as RFA areas are not clearly distinguishable with 11C-5HTP-PET alone. Paper V studied gallstone complications after somatostatin analog treatment in SI-NET patients, and concluded that there was a rather high risk to be subjected to a cholecystectomy due to biliary colic, cholecystitis, cholangitis or pancreatitis after primary surgery in somatostatin analog treated patients.
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8. |
- Annerbo, Maria, 1967-
(författare)
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Calcium Homeostasis in Patients with Graves' Disease
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Patients with Graves´ Disease (GD) have a higher risk of developing more severe and prolonged hypocalcaemia after total thyroidectomy (TT) than patients who undergo surgery for benign atoxic goitre. Since TT is the most effective treatment for GD, it is crucial to identify mechanisms for postoperative hypocalcaemia. The aim of this thesis was to study the mechanisms of calcium metabolism in patients with GD.It is safe to operate on GD patients with TT. Results in Paper I showed fewer recurrences and equal complication rates compared to patients who underwent subtotal thyroidectomy (ST). The transient lowering of PTH seen in the hypocalcaemic patients was fully restored one month after surgery (Papers II and V).The calcium-sensing receptor (CaSR) is crucial for maintaining plasma calcium, and single nucleotide polymorphisms (SNPs) in the gene may alter the sensing function. Thus, we analysed SNPs in CaSR in GD patients (Paper II) and showed that they had a more left-shifted calcium-PTH set-point compared to controls, implicating higher sensitivity. This is also supported by the results in the group of postoperatively hypocalcaemic patients. They already had lower plasma calcium preoperatively (Papers II, IV and V) and lacked the T/G G/A G/C, a haplotype shown in Paper III to have a close relationship to higher p-calcium levels. Moreover, a lack of the T allele in rs1801725 was seen in the group of patients needing permanent treatment with calcium and vitamin D, i.e. > 12 months, (paper V).Patients who became hypocalcaemic (p-calcium < 2.00 mmol/L) on day one postoperatively, had lower preoperative levels of thyroid stimulating hormone (TSH) and higher levels of T3, this was also applied to the patient groups requiring temporary or permanent postoperative treatment (Papers II and V). In addition, hypocalcaemic patients treated for less than six months with anti-thyroid drugs had higher levels of bone metabolism markers CTX and P1NP than normocalcaemic patients (Paper V).In conclusion, the postoperative period of hypocalcaemia seen in patients with GD is a complex medical condition, caused by a combination of surgical trauma, different SNPs in CaSR, and high bone metabolism related to preoperative thyroid metabolism.
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9. |
- Edholm, David
(författare)
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Gastric Bypass : Facilitating the Procedure and Long-term Results
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Gastric bypass achieves weight loss in the morbidly obese. Preoperative weight loss is used to reduce the enlarged fatty liver that otherwise reduces visibility during surgery. The purpose of gastric bypass is to provide patients with long-term weight loss. The aim of this thesis was to investigate the result of preoperative low calorie diet on liver volume and to evaluate the long-term result of gastric bypass.Paper I showed that four weeks of low calorie diet reduces intrahepatic fat by 40% and facilitates surgery mainly through improved visualisation. Paper II demonstrated that all of the reduction of liver volume occurs during the first two weeks of treatment with low calorie diet. In paper I liver volume was reduced by 12% and in paper II by 18%. Paper III focused on long-term results and showed that gastric bypass achieves a mean 63% excess body mass index loss in obese patients after 11 years. However, of these 40% undergo abdominoplasty and 2% require additional bariatric surgery. Only 24% adhere to the lifelong recommendation on multivitamins and 72% to Vitamin B12 recommendations. Paper IV evaluated gastric bypass as a revisional procedure after earlier restrictive surgery had failed. Similar weight results as after primary gastric bypass are attained. No patient taking vitamin B12 supplementation was deficient at follow-up, regardless of whether the vitamin was taken as a pill or as intramuscular injections.
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10. |
- Eriksson, John
(författare)
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Prognostic Factors for Death in Small Intestinal Neuroendocrine Tumours
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tumours in the small intestine are rare compared to those in other gastrointestinal organs. Small intestinal neuroendocrine tumours (SI-NETs) are the most common small bowel tumours with an annual incidence of 0.3-1.7 per 100 000 persons. They are characterised by their usually indolent nature and, even though many patients present with metastatic disease, survival is favourable compared to most other gastrointestinal malignancies. The principal aim of this thesis was to establish prognostic factors over the entire life span of patients with SI-NETs. Paper I confirmed the known prognostic factors of metastatic and symptomatic disease as preoperative prognostic factors. In this paper, we also showed that patients with symptomatic Stage IV disease are the most likely patients to die from their SI-NET. Patients who undergo surgery in an emergency setting fared better than patients who had elective surgery and this can possibly be explained by patients having less advanced disease in emergency procedures. Paper II focused on the perioperative period, during which liver metastases and peritoneal carcinomatosis stood out as the most important prognostic factors. A macroscopically radical surgery had a positive prognostic impact, as did radical locoregional surgery (LRS). In univariable analysis, LRS was a positive prognostic factor regardless of TNM stage. In Paper III, the specific findings that had prognostic impacts in the postoperative period were the negative impacts of carcinoid heart disease and non-radical secondary surgery. The occurrence of a second malignancy seemed to have positive prognostic value but was most likely a result of study design. Paper IV studied expression patterns seen on immunohistochemistry of primary and metastatic tissue sections from the primary operation in 40 patients. In this study, low TFF3 expression in primary tumours was correlated to decreased survival. We also proposed a dual mechanism for TFF3 in the dedifferentiation of SI-NETs based on the finding of high TFF3 expressions in metastatic tissue. The expression of mindin and ACTG2 was higher in G2 tumours and we suggested that mindin played a role as an indirect promoter of proliferation and cell migration. Finally, in Paper V, we calculated the mean annual incidence of clinical and subclinical SI-NETs from autopsy material comprised of the very high number of autopsies from the Malmö region between the years 1970 and 1982. The total mean annual incidence of SI-NETs was 5.7 per 100 000 and males were more likely to harbour a SI-NET than females. In this material, 40% of those with a SI-NET had at least one other malignancy, which constitutes a more than three-fold increased rate of synchronous malignancies in SI-NET cases.
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