Further cytogenetic and molecular analyses, however, identified the Philadelphia chromosome, <i>BCR::ABL</i> rearrangement, and mutations in <i>TP53</i>, <i>KMT2D</i> and <i>STAG2</i>, establishing the diagnosis of MS secondary to CML in extramedullary blast phase. The gene discussed is TP53; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.