RESUMEN
Background: Androgen receptor (AR) has been described to play a prominent role in male breast cancer (MBC). It maps on chromosome X, and recent reports indicate that X-chromosome polysomy is frequent in MBC. Since the response to anti-androgen therapy may depend on AR polysomy and on its overexpression similarly to prostate cancer, the aim of the present study was to investigate the DNA methylation level of AR and its coregulators, especially those mapped on the X-chromosome, that may influence the activity of AR in MBC. Methods: The DNA methylation level of AR, MAGEA2, MAGEA11, MAGEC1, MAGEC2, FLNA, HDAC6, and UXT, mapped on the X-chromosome, was evaluated by quantitative bisulfite-NGS. Bioinformatic analysis was performed in a Galaxy Project environment using BWA-METH, MethylDackel, and Methylation Plotter tools. The study population consisted of MBC (41 cases) compared with gynecomastia (17 cases). Results: MAGEA family members, especially MAGEA2, MAGEA11, MAGEC, and UXT and HDAC6 showed hypomethylation of several CpGs, reaching statistical significance by the Kruskal-Wallis test (p < 0.01) in MBC when compared to gynecomastia. AR showed almost no methylation at all. Conclusions: Our study demonstrated for the first time that MAGEA family members mapped on the X-chromosome and coregulators of AR are hypomethylated in MBC. This may lead to their overexpression, enhancing AR activity.
RESUMEN
Salivary gland like tumours of the breast constitute a wide spectrum of entities each one showing peculiar features and clinical behaviour. They can be subdivided as follows: (1) tumours showing pure myoepithelial cell differentiation, such as pure benign and malignant myoepitheliomas; (2) tumours with mixed epithelial and myoepithelial cell differentiation, such as pleomorphic adenoma, adenomyoepithelioma and adenoid cystic carcinoma; and (3) tumours with pure epithelial cell differentiation, such as acinic cell carcinoma, oncocytic carcinoma, mucoepidermoid carcinoma and polymorphous adenocarcinoma. These tumours share similar features with the salivary gland counterparts, but different clinical behaviour. Most salivary gland type tumours of the breast are negative for oestrogen and progesterone receptor and lack HER2 gene amplification, therefore they are classified as 'triple negative' tumours. Nevertheless, some of the malignant entities (such as classical adenoid cystic carcinoma) exhibit good behaviour and do not need any treatment in addition to local control. The aim of the present paper is to review the morphological and prognostic features of salivary gland like tumours of the breast, in order to highlight the correct clinical management.