[Basal-like breast cancers: clinicopathological features and outcome]

The aim of our study was to investigate basal phenotype in a series of triple-negative (estrogen and progesterone receptors-negative and HER2-negative) invasive mammary carcinomas.

We selected 140 previously tested triple-negative tumors. Clinical, histopathological and survival data were obtained. A tissue microarray containing 2 cylinders from each tumor was constructed and immunohistochemistry for estrogen receptor (ER), progesterone receptor (PR), HER2, cytokeratins (CK) 5 and 14, EGFR, p63, and p53 was performed. We considered basal like-cancers (BLC) those tumors that were ER/PR/HER2-negative and CK5-positive.

We found 105 cases of BLC from 140 triple-negative tumors (frequency=75.0%). The mean age at diagnosis was 54.8 years-old and 34.3% were premenopausal women. The majority of tumors were high grade (83.7%) and of ductal/no-special-type (80.8%). Triple-negative tumors showed immunoreactivity for CK5 (75.0%), CK14 (29.0%), EGFR (28.6%), p63 (28.6%), and p53 (67.1%). Tumor size larger than 5cm was observed in 41 cases (39.0%) and axillary metastases were detected in 61 patients (59.2%). Follow-up was recorded for 89 patients (mean=51 months): 45 patients (50.5%) with no evidence of disease; 6 patients (6.7%) were alive with disease; and 38 patients (42.6%) died of the disease. Relapse was detected in 42 women (47.1%), lungs, brain, and bones being the most common sites of metastasis. The mean overall survival was 36 months and the mean disease-free interval was 28 months.

Our findings confirmed that BLC are poor prognosis and highly-frequent carcinomas among triple-negative tumors, similar to data previously reported in North American and European patients.