Lymphocytic Inflammation Is A Distinct Feature Of Squamous Metaplastic Breast Carcinomas And Is Associated With Metastasis

Metaplastic breast carcinoma (MBC) is a rare subtype of triple negative breast carcinoma with frequent metastasis and poor response to chemotherapy. MBCs are defined by the presence of “metaplastic” components of spindle, squamous, or sarcomatoid histology (e.g. chondroid, osseous). To elucidate the molecular determinants of MBC, our lab analyzed the proteomics landscape of MBC which revealed that squamous MBC are significantly enriched for proteins that mediate inflammation and leukocyte activation, compared to spindle and sarcomatoid MBC. The presence and the significance of inflammation in MBC has not been investigated. To evaluate this, we retrieved 36 MBCs resected from 1988-2015 at our institution. Tumor sections were reviewed by three pathologists, and used to develop a tissue microarray (TMA) in duplicate. HE 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 981.