Moreover, much larger numbers of cancer cells exhibiting chromosome 7 amplification (copy number >4/cell), on which the MDR1 gene is located, were observed in the TP53 mutant group (2.1 ± 0.7)% than in the wild-type group (0.3 ± 0.05)% (p < 0.01) (Fig. 4b). The gene discussed is TP53; the disease is cancer.