In accordance with previous reports, our analysis reveals a higher frequency of high grade and endocrine insensitive breast tumors in young women as compared to older women, as well as age-related differences in the relative frequency of breast cancer subtypes by age [15], Specifically, we found an increased frequency of HER2-enriched and basal breast cancer subtypes in young as compared to older women. This evidence concerns the gene ERBB2 and breast neoplasm.