On the other hand, p53 gene serum levels were higher in patients with CML compared to the healthy subjects because, under normal conditions, the p53 gene turnover is preserved at a high level via MDM2 that activates proteosome-mediated p53 gene degradation causing auto-regulatory feedback [16]. The gene discussed is TP53; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.