HER2 expression in Brazilian patients with estrogen and progesterone receptor-negative breast carcinoma.

The aim of the study was to evaluate the relationship between clinical and pathological factors and survival in patients with double negative HER2-overexpressing carcinoma and triple negative carcinoma. One hundred and sixty-one (161) patients diagnosed with breast cancer negative for estrogen receptor (ER) and progesterone receptor (PR) were included. Of the total, 58 patients had double negative HER2-overexpressing (ER/PR-negative and HER2-positive) and 103 had triple negative (ER-negative, PR-negative and HER2-negative). ER and PR expression was assessed through immunohistochemistry (IHC) and HER2 expression was measured by immunohistochemistry and Fluorescent in situ Hybridization (FISH) analysis in tissue microarray. More than 80% had stages II and III disease and histologic grade III and nuclear grade 3. Patients with triple negative breast carcinoma had undifferentiated histologic types in 11% of cases and vascular invasion in 14.5%. Both groups had more than 50% visceral metastases. HER2 expression (p=0.42) and vascular invasion (p=0.05) did not interfere with survival. Survival of patients with Stages I-II disease was significantly longer than in those with Stage III disease both for double negative HER2-overexpressing carcinomas (p<0.0001) and triple negative carcinomas (p=0.03). The study shows that hormone receptor-negative breast carcinomas were undifferentiated and diagnosed at advanced stages and that HER2 expression was not associated with overall survival.