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- 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. |
- Niméus, Emma
(författare)
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Prognostic and treatment predictive factors for radio- and chemotherapy resistance in breast cancer patients- a step towards personlized medicine
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Breast cancer is the most common cancer form among women in the Western world. Although treatment has improved during the last decades, there is still a significant proportion of the patients who are not cured. To further improve clinical outcome we need new treatment strategies, new prognostic markers, and new treatment predictive factors for personalized medicine.In this dissertation I have focused on local relapse and distant recurrences, where the former is a tumor recurring in the same breast and the latter is distant spread in the body. I have focused on high through-put techniques, but have also evaluated one single factor, using immunohistochemistry. The most promising result is the gene expression profile for “radioresistance” found in a patient cohort consisting of 100 lymph node negative patients operated with breast conservation surgery and either postoperative radiotherapy or not. The samples were analyzed with oligonucleotide array. A gene expression profile was found that clearly separated patients who developed local recurrences despite radiotherapy (“radioresistance”) from patients without local recurrences (either with or without radiotherapy). The clinical consequence, if these results can be confirmed, would be that patients with a“radioresistant” gene profile should be offered mastectomy instead of breast conservation surgery and radiotherapy. In another patient cohort consisting of 85 node positive breast cancer patients treated with CMF (cyclophosphamide, methotrexate, and 5-fluorouracil) we found a gene expression profile, using cDNA microarray, capable of distinguishing patients who developed distant recurrences from non-recurring patients. This profile was compared to a previously published gene list and to drug-associated genes from the literature. Our results were slightly better. However, our gene profile was not able to exceed the performance of conventional clinical markers. From the same patient cohort, we developed a protocol for protein extraction from the same samples used for RNA. We analyzed the protein expression pattern using 2-DE (two-dimensional electrophoresis) and found several differentially expressed proteins, both when comparing distant recurrences to no recurrences and estrogen receptor positive to estrogen receptor negative tumors. Similarities of regulated genes and proteins were also found when comparing the two studies. Finally, we investigated the prognostic importance of a proliferation marker, cyclin B1,in a case-control study. There were 190 lymph node negative breast cancer patients with no chemotherapy who died from breast cancer and 190 corresponding controls who were alive at the corresponding case’s time of death. Cyclin B1 was an independent prognostic proliferation marker and had a high reproducibility. The marker may be useful instead of histological grade, or as a complement, to identify patients in need of adjuvant chemotherapy. In conclusion, breast cancer is a heterogeneous disease and should be subdivided even more than it is today into different risk groups with the aid of new markers. We used different high through-put techniques to analyze hundreds to thousands of gene expressions and proteins. Our aim was to find new prognostic and predictive gene expressions and protein profiles that may improve individual treatment schemes and help provide personalized medicine. However, so far it is too early to conclude that the use of single markers can be eliminated, because we also found significant prognostic value of the proliferation marker cyclin B1.
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