Expression of MAGE-A11 in breast cancer tissues and its effects on the proliferation of breast cancer cells.

The melanoma-associated antigen (MAGE) genes are commonly expressed in tumors, but the function of many of these genes remains unknown. Here, we investigated the expression of one family member, MAGE-A11, in breast cancer tissues and corresponding adjacent normal tissues. MAGE-A11 expression was assessed in breast cancer tissues and adjacent normal tissues from 100 women by immunohistochemistry. MAGE-A11 was significantly more highly expressed in breast tumors (56% of samples) compared to normal tissues (0%; P<0.05). Additionally, its expression in breast tumors was investigated in relation to various clinicopathological features, including patient age, tumor stage and volume, and lymph node metastasis. MAGE-A11 protein expression was correlated with expression of the human epidermal growth factor receptor-2 (HER-2) and estrogen receptor (ER)-β (P<0.05), but not with age, pathological type, histological grade, clinical stage, tumor size or lymph node metastasis, or ER-α, progesterone receptor (PR) or amplified in breast cancer 1 (AIB-1) expression. To determine how its expression affects cancer cell proliferation in vitro, MCF-7 human breast cancer cells were transfected with pCMV-AC-MAGE-A11-GFP. MTT colorimetry and colony-forming assays indicated that MAGE-A11 overexpression significantly increased breast cancer cell proliferation and the ability to form colonies (P<0.05). These findings indicate that MAGE-A11, similarly to HER-2 and ER-β, may be an important diagnostic or prognostic indicator in breast cancer and potentially promotes tumor proliferation.