ERBB2 and cancer: Mastectomy rates were highest for the luminalsubtypes, mastectomy being performed in 102 (76%) of the 134 cases of luminal breastcancer, compared with 55 (39%) of the 141 cases of luminal B HER2+ or HER2-enrichedbreast cancer and 51 (57%) of the 90 cases of triple-negative breast cancer.