Chromosomal characteristics of Ph-positive chronic myelogenous leukemia in transformation: A study of 23 Chinese patients in Taiwan

Abstract

Cytogenetic study was performed in the past 3 years on 23 Chinese patients with Philadelphia chromosome (Ph) positive chronic myelogenous leukemia (CML) in transformation; seven were in accelerated phase and 16 in acute blast crisis. Chromosomal abnormalities in addition to Ph were found in three (43%) of the patients at accelerated phase and 14 (88%) of the patients at blast crisis. The common nonrandom chromosomal aberrations were double Ph, trisomy 8, trisomy 19, and trisomy 21, which occurred in 47%, 41%, 35%, and 29%, respectively, of the total patients with extra chromosomal abnormalities. Isochromosome for the long arm of chromosome 17 was found in only one patient. In patients with blast crisis, the type of blast cell was characterized through morphologic, cytochemical, and immunocytochemical studies. Eleven cases were classified as myeloid and five as lymphoid transformation. Trisomy 8, 19, and 21 were detected only in patients with myeloid blast crisis. This study also revealed a high incidence of trisomy 21 and a low incidence of i(17q) in Chinese patients with transformation of CML.