[The practical value of breast cancer molecular classification]. / Praktyczna wartosc molekularnej klasyfikacji raków sutka.

Breast cancer is the most common female cancer in the Western World and the leading cause of cancer death among women. It is a clinically heterogeneous clinical entity. Histologically similar tumors may have different prognosis and may respond to therapy differently. It is believed that these divergences in clinical behavior are due to molecular differences between microscopically similarneoplasmas. Breast cancer is a complex disease of genetic background characterized by accumulation of molecular alterations resulting in an important clinical heterogeneity. Current prognostic factors (including lymph node status, tumor size, histological grade, hormone receptor status, ERBB2 expression and patient age) are insufficient to predict accurately the clinical outcome. Microarray expression profiling classifies breast cancer into five (or six) molecular subtypes: luminal A, luminal B, basal-like, HER2 and normal breast-like (sometime luminal C, too). The different molecular classes of breast cancer not only have different prognoses but also show distinct sensitivities to preoperative chemotherapy. They have specific clinical profiles, as well (reproductive factors, age and race). It means that new, modified prevention strategy for breast cancer is necessary.