ERBB2 and breast carcinoma: Although several studies have shown no significant differences in survival according to age in hormone receptor–negative breast cancer, it has been reported that hormone receptor–positive breast cancer diagnosed at a younger age has a poorer survival outcome.11,12 Because young patients with hormone receptor–positive, ERBB2-negative breast cancer have a relatively long life expectancy, the cumulative risk of late recurrence after 5 years in younger patients is greater than that of older patients, which should be considered in the treatment of young patients with breast cancer.