Large genomic analyses have provided crucial insights into the genetic landscape of breast cancer.8–14 For example, a high prevalence of PIK3CA mutations and cyclin D1 amplification are observed in the luminal subtypes, whereas a high prevalence of mutation in TP53 and alterations in DNA repair enzymes are observed in the basal-like subtype of breast cancer. This evidence concerns the gene CCND1 and breast carcinoma.