ERBB2 and breast cancer: Furthermore, hormone receptor-negative, HER2 positive, and triple-negative cancers, which are poor prognostic factors, are also more common in young women.14, 15, 16, 17, 18, 19, 20 These are comparable to our study group of young women, which includes hormone receptor-negative (38.8%), HER2-positive (39.3%) and triple-negative (26.8%) breast cancers.