May metaplastic breast carcinomas be actually basal-like carcinoma? Further evidence study with its ultrastructure and survival analysis

Metaplastic breast carcinoma (MBC) encompasses a heterogeneous group of tumors. Based upon the microarray of MBCs, these tumors showed features of basal-like carcinoma and myoepithelial differentiation. However, MBCs entity still remained unclear. So we performed a systematic research to explicit metaplastic breast carcinomas further. A panel of ER, PR, HER-2, CK5/6, CK14, P63 and EGFR were prepared for detection of MBCs, and fluorescence in situ hybridization for HER-2 gene amplification and ultrastructure observation were also performed. Sensitiveness between CK5/6 and other antibodies in diagnosis was analysed, and survival analysis was also carried out. ER, PR and HER-2 were negative. CK5/6 (12/12), CK14 (9/12), EGFR (10/12) and P63 (8/12) were positive. FISH for HER-2 displayed no amplification (ratio values < 1.8). Ultrastructure showed tonofibrils, thin filament and dense body in the cytoplasm. Significant statistical differences were detected between groups (F = 8.080, P = 0.000) of score of CK5/6, CK14, P63 and EGFR. Significant statistical differences were also detected between age and lymph node involvement and survival (χ² = 10.835, P = 0.004). MBCs may be actually basal-like carcinomas. In the diagnosis of MBCs, CK5/6, CK14, P63 and EGFR may be effective and CK5/6 may be more sensitive than CK14 and P63. Survival of MBCs may be associated with age and lymph node involvement. However, given the limitations of our research accumulated cases, prospective clinicopathologic studies are needed to further elucidate MBCs.