Abstract

Breast carcinoma is the most common malignancy in females in western countries. Classical prognostic factors such as the size of a primary tumor and the presence or absence of axillary lymph node metastases, malignancy grade and hormone receptor status reflect the subsequent risk of disease recurrence after primary therapy and the need for adjuvant therapies. However, most breast carcinomas are detected in the early stage of the disease and the value of these classical prognostic factors is limited. There is also a great need to find new factors predicting the clinical efficacy of the anticancer drugs available. In this thesis tumor suppressor gene p53, oncogene c-erbB-2 and matrix metalloproteinase-9 were evaluated for their prognostic relevance in breast carcinoma patients treated in Oulu University Hospital, and matrix metalloproteinase-9 was also analyzed in women with premalignant lesions in the breast tissue in order to examine its role in breast carcinogenesis. Histological analyses were carried out from formalin-fixed, paraffin-embedded primary tumor specimens and p53, c-erbB-2 and matrix metalloproteinase-9 (MMP-9) statuses were systematically analyzed by immunohistochemistry.

P53 expression correlated with disease-free survival and overall survival in patients with early-stage breast carcinoma, regardless of adjuvant antiestrogen therapy. The co-expression of p53 and c-erbB-2 characterizes a tumor type with a clinically aggressive course of breast carcinoma. The clinical efficacy of anthracyline-based chemotherapy in metastatic carcinoma might be limited in patients with p53 expression in a primary tumor. When postmenopausal patients with lymph node metastases and receiving adjuvant antiestrogen therapy were examined, MMP-9 expression indicated a slightly greater risk of breast carcinoma recurrence in patients with estrogen receptor negative tumors. Hyperplastic breast tissue and invasive breast carcinoma lesions expressed some MMP-9 immunopositivity. However, the strongest positivity was seen in ductal carcinoma in situ samples, suggesting that MMP-9 participates in breast carcinogenesis in the preinvasive phase.