Male breast cancer is a rare form of carcinoma with an incidence rate of approximately 0.5-1% compared with cases of breast carcinoma as a whole. Male breast cancer reacts effectively to endocrine therapy because of a high frequency of hormone receptor expression.The aim of the present study was the assessment of correlations between stage, grade, expression of steroid receptors, basal/mesenchymal markers and proliferation index, as well as analysis of the impact of the above-mentioned parameters on overall (OS) and disease-free survival (DFS) in the group of 32 male breast cancer patients, treated at the Centre of Oncology in Cracow.We showed the significant positive correlation between MIB-1 LI and tumor stage, and hormone receptors (ER or PgR) immunonegativity, and expression of EGFR, vimentin (p<0.05) and P-cadherin (the last at statistical border). The presence of any of basal or masenchymal markers correlated with a more advanced tumor stage. Moreover tumors without vimentin expression were characterised by lower MIB-1 LI and were more frequently EGFR immunonegative.We found that hormone receptor negativity, vimentin immunopositivity and high MIB-1 LI are significant independent indicators of poor OS and DFS for male breast cancer patients (p<0.05).
Key words: male breast cancer, basal markers, mesenchymal markers, nodal status, hormonal receptorsMale breast cancer is a rare form of carcinoma with an incidence rate of approximately 0.5-1% compared with cases of breast carcinoma as a whole [1,2,3,4]. Its peak incidence is noted in the seventh decade of life [5,6,7]. The most significant risk factors are an increased concentration of estrogen and obesity, that are a result of estrogen overproduction, impaired metabolism, and disturbances in the concentration of estrogen and androgen (i.e. in Klinefelter's syndrome) as well as the use of estrogenes in prostate cancer treatment [6,8,9,10,11]. Other factors include alcoholism, liver cirrhosis, the presence of hereditary BRCA1 and BRCA2 gene mutations and exposure to ionizing radiation, the electromagnetic field and increased temperature [6,8,9,12,13,14,15,16,17].According to Anderson et al., male breast cancer is characterised by similar biological factors to those present in the female variant of the cancer [18]. However, these tumors are diagnosed in more advanced stages of the disease, are characterised by higher degree of differentiation (more frequently G1, G2 grade) and a lower mitotic index in comparison to female breast cancer [5,19]. There are also differences in the frequency of the expression of hormone receptors and growth factor receptors [19,20]. Besides, the prognosis for male breast cancer is worse [5,18,20,21]. A study by Baojiang et al. of 5-year survival rates of patients suffering from male breast carcinoma and female breast carcinoma produced the following results: 61.2% and 68.7% (DFS), and 75.% and 82.9% (OS), respectively [20].Male breast cancer has a higher (over 90%) hormone receptor expression and, as a consequence, reacts more effect...