Previous studies have noted poor outcome associated with high expression of cytokeratin 5, 6A and 6B in basal tumors [5], but to our knowledge this is the first report that the association between cytokeratin expression and inferior DFS may be an age-related finding, present in young women with HER2-enriched as well as basal tumors, but not in older women with breast cancer. This evidence concerns the gene KRT5 and breast cancer.