[Bcl-2 as a prognostic factor in different molecular genetic subtypes of breast cancer]

It is well known that breast cancers (BC) are divided into 4 molecular genetic subgroups (luminal A, luminal B, HER2/neu-positive, and triple-negative (TNBC). The purpose of the investigation was to comparatively estimate the pattern of expression of Bcl-2, known as a good prognostic marker of BC, in different molecular genetic subgroups and to study the correlation of this protein with proliferative activity index and genetic aberrations on chromosome 17. The investigation covered 290 samples of invasive ductal BC. Bcl-2 expression was identified in 14% of HER2/neu-positive and TNBC cases while 77% of luminal B tumors and 100% of luminal A ones expressed Bcl-2. Loss of Bcl-2 expression correlated with clinically more aggressive BCs having a high proliferative activity and amplification of HER2/neu and chromosome 17 centromere. This may suggest the poor prognosis of luminal B, HER2/neu-positive and TNBC with no Bcl-2 expression and calls for further investigations on larger samples.