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- Ahnström Waltersson, Marie, 1976-
(författare)
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Cell cycle alterations and 11q13 amplification in breast cancer : prediction of adjuvant treatment response
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The growth and development of the breast is to a large extent regulated by oestrogens through the oestrogen receptor (ER). Activation of the ERα triggers transcription of genes that are important for cell proliferation and stimulates entry into the G1 phase of the cell cycle. In breast cancer the ERα is often upregulated and is therefore a suitable target for adjuvant therapies such as tamoxifen. Although tamoxifen is an effective treatment in most cases, tumours sometimes acquire resistance to the drug. The aim of this thesis was to investigate the impact of G1 phase proteins and 11q13 amplification on prognosis and treatment response in breast cancer. The material used was from a clinical trial in which postmenopausal breast cancer patients were randomised to chemotherapy or radiotherapy and tamoxifen or no adjuvant treatment. We studied the expression of cyclin D1, cyclin E and Rb with immunohisochemistry and amplification of CCND1 and PAK1 with real time PCR. We found that among patients with high tumour expression of cyclin D1, overexpression of ErbB2 was associated with reduced recurrence-free survival. Both cyclin D1 and cyclin E overexpression were associated with reduced tamoxifen response. High expression of cyclin D1 has been found to induce ligand independent activation of ERα in breast cancer cells and might also switch tamoxifen from acting as an antagonist to an agonist. Overexpression of cyclin E has been shown to be associated with expression of low molecular weight isoforms of the protein that possess an increased kinase activity and are insensitive to p21 and p27 inhibition. Furthermore, amplification of 11q13, and in particular the gene PAK1, was a strong predictor of tamoxifen resistance. The pak1 protein is involved in phosphorylation and ligand independent activation of the ERα. We also found that lost expression of either p53 or Rb reduced the patients benefit from radiotherapy compared with patients with normal expression of both proteins. Normally, ionizing radiation upregulates p53 resulting in G1 arrest or apoptosis. If either functional p53 or Rb is missing the cells can proceed from G1 to the S phase despite damaged DNA. The expression of the microRNA, miR-206, was analysed with real time PCR, and the results showed that high expression of miR-206 correlated to low expression of ERα and 11q13 amplification. In vitro studies have shown that miR-206 negatively regulates the expression of ERα. Taken together the G1 regulators and amplification of 11q13 seem to have an important role in predicting the patient’s response to adjuvant therapy.
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| 2. |
- Koliadi, Anthoula
(författare)
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The Prognostic Impact of Proliferation Markers in Breast Cancer with Emphasis on Cyclin B1 and PPH3
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to investigate the prognostic role of the proliferation markers cyclin B1 and Phosphorylated Histone 3 (PPH3) in breast cancer (BC).In paper I we used an experimental study design, we compared women dying early from their BC with women free from relapse more than eight years after initial diagnosis. All women had stage I, node-negative and hormone receptor positive disease. None had received adjuvant chemotherapy. We found that low-risk node negative patients with high expression of cyclin B1 had a significantly worse outcome than patients with low expression of cyclin B1.In paper II a population-based case control study was performed to further investigate the prognostic value of cyclin B1. One hundred and ninety women who died from BC were defined as cases and 190 women alive at the time for the corresponding case’s death were defined as controls. Inclusion criteria were tumor size 50 mm, no lymph node metastases, and no adjuvant chemotherapy. Two investigators evaluated the stainings independently. Cyclin B1 was found to be a prognostic factor for BC death that could identify high-risk patients with a good to very good reproducibility.Paper III aimed to investigate the role of proliferation in male breast cancer (MBC). One hundred and ninety-seven MBC tumors were stained for cyclin A, B1, D1 and Ki67. Overexpression of cyclin A and B1 and elevated mitotic count were predictive of breast cancer death. Ki67 was re-evaluated and different cut-offs were used, but no prognostic value could be demonstrated. On the other hand high levels of cyclin D1 were associated with better outcome in MBC.In paper IV we applied the immunohistochemichal panel suggested from international guidelines to the same patient material as in paper II, to discriminate luminal A from luminal B BC. We wanted to evaluate if different cut-off values of Ki67, cyclin A or B1 could more clearly separate luminal A from B. Cyclin A, B1 and Ki67 (cut-off 20%) could detect difference in outcome between these subtypes with cyclin A showing greater prognostic value.The aim of paper V was to examine the prognostic role of PPH3 compared to the proliferation markers Ki67, cyclin A and cyclin B1 with focus on ER positive disease. PPH3 was found to be a prognostic factor for breast cancer death but in the multivariate analysis including all proliferation markers, only cyclin A remained a prognostic factor.Finally, we conclude that both cyclin B1 and PPH3 are prognostic factors for breast cancer death, but are outperformed by cyclin A in ER positive patients. In male breast cancer prognostic factors need to be further studied.
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| 3. |
- Nilsson, Cecilia, 1971-
(författare)
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Characterization of Male Breast Cancer : From Molecule to Clinical Outcome
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to investigate different aspects of male breast cancer (MBC), and to compare these with findings in female breast cancer (FBC). In paper I, a population–based study was performed to investigate possible differences in treatment and outcome between MBC and FBC patients. MBC and FBC presented with a similar distribution of stage. Although no differences in primary treatment strategy were demonstrated, MBC patients had significantly poorer overall and relative survival, indicating a more aggressive disease. Paper II aimed to assess the value of clinicopathological factors and molecular subtypes in MBC. One hundred and ninety-seven MBC tumors were characterized using immunohistochemistry (IHC) and the findings were correlated to outcome. Lymph node positivity, larger tumor size and ER-negativity were independent risk factors for breast cancer death. Tumor grade, HER2, Ki 67 or IHC classification into molecular subtypes did not demonstrate any prognostic information. In paper III, the same patient material as in paper II was used for evaluation of proliferation markers. High levels of cyclin A and cyclin B expression and an elevated mitotic count were predictive of breast cancer death. Ki-67 was re-evaluated using different cut-offs, but no prognostic value could be demonstrated. Contrarily, overexpression of cyclin D1 was associated with a lower risk of breast cancer death. In papers IV-V, the molecular background of MBC tumors was investigated. Global GEX analyses were performed and two novel subgroups of MBC tumors were identified; luminal M1 and luminal M2. When comparing the degree of similarity with the “intrinsic” subtypes in FBC tumors, more than half of the MBC tumors remained unclassified. Comparative genomic hybridization was used to investigate DNA aberrations. Two MBC subgroups were identified, of which one did not resemble any of the female subgroups. In both studies on the molecular level, a majority of patients were classified into the subgroup with a more aggressive tumor behavior. In conclusion, MBC seems to be a unique tumor entity. The established molecular subtypes in FBC are not applicable in MBC. Other prognostic profiles, specific for MBC, need to be identified.
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