Female breast cancer status according to ER, PR and HER2 expression: a population based analysis

The aim of this study is to evaluate the prognostic values of some biological parameters in a population based series of female breast cancer patients. Through the Tuscan Cancer Registry all the invasive breast cancer cases diagnosed during the period 2004-2005 in the provinces of Florence and Prato, central Italy, were retrieved. Molecular subtypes were analyzed defined by immunohistochemical markers, by age, tumor size, lymph node status, histotype, grade of differentiation and proliferative marker. Out of 1487 patients 70.3% were luminal A subtype (ER/PR + HER2-), 15.6% luminal B (ER/PR + HER2+), 8.1% triple negative (ER/PR-HER2-), 6.0% HER2+ (ER/PR-HER2+); the 3 year survival rates were 93.3%, 89.5%, 86.3%, 82.7% respectively (p < 0.001). Analysis of survival by the Cox proportional hazards model showed an independent prognostic value of molecular classification. Our study revealed significant differences in clinicopathological characteristics among breast cancer molecular subtypes and confirmed their prognostic independent role.