Figure 1.

U.S. Incidence of Breast Cancer Subtypes, by Hormone Receptor and HER2 Status as Recorded in 2010 SEER Registries

The Surveillance, Epidemiology, and End Results (SEER) registries cover about 28% of the U.S. population. In these nationally representative registries, the molecular subtypes according to hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status were known in 50,571 of the 2010 total of 57,483 breast cancer cases but were unknown in 6,912 cases (12% of the total). The HR+, HER2− molecular profile accounted for 73% of the cases for which status was known.³