Myelomonocytic crisis with t(5;17) and a p53 mutation in a patient with chronic myelogenous leukemia

We report a 64‐year‐old Japanese man with chronic myelogenous leukemia (CYL) who expired with myelomonocytlc crisis. Cytogenetic analyses of chronic phase (CP) and accelerated phase (AP) cells revealed a Philadelphia chromosome and an isochromosome for the long arm of chromosome 17, i(17q). This karyotype was replaced by another karyotype in blast crisis (BC), resulting in near triploidy with t(5;17) (p15;p11) and loss of chromosome 17pter→p11. Interphase fluorescent in situ hybridization studies with a chromosome 17 specific alpha satellite DNA probe confirmed the presence of a clonal change in BC. In addition, singie‐strand conformation polymorphism analysis and PCR‐direct sequencing of BC cells revealed a point mutation at codon 203 of the p53 gene, GAG to GAG (Val to Glu), and loss of the normal allele. In contrast, no alterations of the p53 gene were found in CP and AP cells. Therefore, progression of CML in this patient appeared to be related to loss of 17p, as well as a mutation in the p53 gene. © 1994 Wiley‐Liss, Inc.