Breast cancer is the most common malignancy in women. It is an immensely heterogeneous disease, characterized by a broad variety of clinical development. The research in recent years has focused on finding new markers of prognostic significance. Bcl-2, the protein product of the Bcl-2 gene, is a member of the Bcl-2 family of proteins that play a crucial role in a complex mechanism of apoptosis. It was recently proposed that Bcl-2 could inhibit cancer progression.