The variations affected cancer genes such as BRCA1, TP53, KRAS, and PIK3CA. These variants were frequently not detectable at P0 and became detectable at P1 with the allelic fractions centered on 0.5 (heterozygous somatic mutations) in models at P1–P3 and in the established PDX at later passages. The gene discussed is TP53; the disease is cancer.