Metaplastic Breast Cancer and EGFR Expression

Aim: Metaplastic breast cancer has poor prognosis and is usually triple negative. Although it is morphologically more heterogeneous than triple negative breast cancers, expression profile is more homogeneous. In this study, we investigated our metaplastic breast cancer cases regarding their pathology and clinical characteristics. Material and Method: 16 metaplastic breast cancer cases from four different center were included in the study. Pathology and clinical characteristics of the cases were evaluated retrospectively. Results: All the cases are female and median age is 48 (39-45). Tumor is commonly localized to the outer quadrant and mean diameter of the mass is 37.5 (15-100) mm. Tumor diameter is ≤20 mm in 3 (15.8%), >20-≤50 mm in 11 (57.9%) and >50 mm in 3 (10.51%) of the cases. Only 4 (16.1%) patients have axillary lymph node involvement. When considering histological subtypes, five of the cases has squamous cell, five of them has spindle cell, one of them has mucoepidermoid, and in five cases the subtype was not identified. Considering hormone receptor status ER and PR was negative in 78.9%, 63.2% respectively. HER2 protein expression was positive by immunohistochemical staining in 1 (5.3%) case. CK5/6 and CK17 was both positive in 7 (36.8%) cases. EGFR expression was positive in 4 (21.1%) cases, was negative in 5 (26.3%) cases and not identified in 7 (36.8%) cases. Three of the cases were offered neoadjuvant chemotherapy. As neoadjuvant chemotherapy, anthracycline and taxane combination (n:2 TAC, n:1 AC-paclitaxel) was preferred. Mean follow-up was 41 months. Mean survival was 42.4 months in EGFR negative patients and 47.5 months in EGFR positive patients. This difference was not statistically significant. During follow-up 3 cases had recurrence. Discussion: EGFR expression is seen in metaplastic breast cancer. Although EGFR expression is related to poor prognosis, it is not a predictive marker. Therefore, predictive molecular markers are required for new approaches in treatment