ER-negative breast cancer has a poorer outcome than the ER positive disease in the short term, but in the long term, ER-negative disease subtypes actually have a better prognosis, according to a recent study in PLoS Medicine. Triple negative breast cancers can be divided into basal and non-basal, with the basal subtype having a poorer prognosis.
Survival patterns were independent of treatment, the researchers say, indicating that the biology of the tumor is the essential prognostic factor.
Three ER-negative subtypes exist, termed basal-like, HER2-positive, and normal breast-like tumors. Basal-like breast cancer is commonly identified by a lack of ER and HER2 receptor expression and by the expression of either cytokeratin 5/6 or epidermal growth factor receptor (EGFR). Many, but not all, triple-negative breast cancers are basal-like.
Read the entire study here.
Blows FM, Driver KE, Schmidt MK, Broeks A, van Leeuwen FE, et al. (2010) Subtyping of Breast Cancer by Immunohistochemistry to Investigate a Relationship between Subtype and Short and Long Term Survival: A Collaborative Analysis of Data for 10,159 Cases from 12 Studies. PLoS Med 7(5): e1000279.doi:10.1371/journal.pmed.1000279