ERBB2 and neoplasm: In relation to tumor subtype, the youngest age group displayed a rather unfavorable subtype distribution, with only 39.9% of patients presenting with the subtype HR+ HER2–, 16.9% presenting with the subtype HR+ HER2+ , 7.4% presenting with the subtype HR– HER2+ , and 35.8% presenting with the subtype HR– HER2–.