In this work we have found some important genotypic similarities between mouse and human cognate cancers, such as the MYC gain and the RB/INTS6 loss, but also important differences such as the chromosome 10 gain in mouse Brca2Δ/Δ;p53Δ/Δ tumors and the 3q gain in human BRCA1-mutated tumors. The gene discussed is MYC; the disease is cancer.