Additional chromosomal abnormalities and variability of BCR breakpoints in Philadelphia chromosome/BCR-ABL-positive acute lymphoblastic leukemia in Taiwan.
From 1986 to 1998, 26 (23%) of 114 adult acute lymphoblastic leukemia (ALL) patients and 11 (4%) of 328 pediatric patients were found to have Philadelphia (Ph) chromosome. In the 30 patients with available data at diagnosis, 18 (60%) had extra-chromosomal abnormalities. They included 1q duplication (5/18, 28%), supernumerary Ph chromosome (4/18, 22%), 9p abnormalities (3/18, 17%), 7q deletion/monosomy 7 (3/18, 17%), trisomy 19 (1/18, 6%), and trisomy 8 (1/18, 6%). Excluding those with specific cytogenetic changes, only one patient had hyperdiploid karyotype with more than 50 chromosomes. The incidence of 1q duplication was higher and that of hyperdiploidy was lower in this study than has been previously reported. There was no prognostic implication of these additional cytogenetic abnormalities. With fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR), 14 (27%) of 53 unselected adult ALL patients and 2 (5%) of 38 unselected pediatric patients were BCR-ABL-positive, including one adult and two children without Ph chromosome. The BCR-ABL fusion genes/transcripts were also present in all other 16 selected Ph-positive ALL patients. The BCR-ABL fusion subtypes were determined in all these 32 patients: 91% (11/12) childhood cases showed m-type fusion gene while 45% (9/20) adult ones did so (P = 0.0083). The clinical outcome was similar between the two groups of patients with m-type and M-type BCR-ABL. In conclusion, both cytogenetic and molecular studies are very helpful for identifying the subgroup of ALL patients with Ph/BCR-ABL. The additional cytogenetic abnormalities and subtypes of BCR-ABL fusion genes/transcripts had no significant implications in this group of patients.
Ko
Bor-Sheng
BS
Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Tang
Jih-Lu
JL
Lee
Fen-Yu
FY
Liu
Ming-Chi
MC
Tsai
Woei
W
Chen
Yao-Chang
YC
Wang
Chiu-Hwa
CH
Sheng
Ming-Chin
MC
Lin
Dong-Tsam
DT
Lin
Kai-Hsin
KH
Tien
Hwei-Fang
HF
D000199:Actins / Q000235:genetics; D000293:Adolescent; D000328:Adult; D002869:Chromosome Aberrations; D017931:DNA Primers; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D016313:Genes, abl / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics*; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000199:Actins; D017931:DNA Primers; D016044:Fusion Proteins, bcr-abl