Frequency of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative invasive breast cancer, the so-called triple-negative phenotype: a population-based study from Trentino, North East Italy.

摘要

Triple negative breast carcinomas (TNT) are infiltrating breast carcinomas (BC) with negative oestrogen receptor (ER), progesterone receptor (PgR) and human epidermal growth factor receptor 2 (HER-2) expression, and are associated with frequent BRCA1/BRCA2 mutations. The aim of the present study is to analyze the frequency and distribution of TNT in our population where a breast cancer screening program for women aged between 50 and 69 years is effective since 2001 with 85% accrual. We investigated the records of 2112 consecutive BC and 153 interval BC (i.e. BC detected in the screened negative women in the interval between screening rounds). Tumours with complete negative expression of ER, PgR and Her2 were considered TNT; tumours with negative ER and PgR status and faint Her2 expression (score 1) were considered as possible TNT (pTNT). We identified 82 (3.8%) TNT and 20 (0.9%) pTNT in the series of 2112 consecutive BC and 7 TNT and 1 pTNT (5.2%) in the series of 153 interval BC. In the consecutive series, TNT/ pTNT were observed in 6.5% patients below 50 years and in 4.3% of patients above 50 years. A high proliferation rate (Ki-67 labelling > 36%) was observed in 87.8% of TNT (median labelling 56.3%) and in 60% of pTNT (median labelling 48.4%). Since TNT/pTNT occurring in women < 50 years is a criterion for selecting patients whom genetic counselling and BRCA1 testing should be offered, our study is of help in foreseeing the workload of the Unit of Medical Genetics and the Laboratory of Molecular Pathology.