Future work will be needed, in a larger set of TNBC patients, to determine if: (1) tetraploidy through chromosome loss is a common mechanism of genome evolution; (2) large numbers of private mutations are common in tumor subpopulations; (3) tumor subpopulations are often geographically segregated with the tumor mass; and (4) early mutations in TP53 drive tumor growth in breast cancer. This evidence concerns the gene TP53 and breast cancer.