Molecular characterization is considered a part of the routine work-up of c
hronic myeloid leukemia (CML) cases. Southern blot analysis using the unive
rsal BCR (UBCR) probe on BglII-digested DNA samples is the most commonly us
ed technique, while employing the human 3' bcr probe (PR-1) is usually cons
idered a complementary tool. In this study, we tried to develop a simple an
d economic strategy for molecular characterization of Ch lt using the 3' pr
obe as it has been shown to be the one capable of locating the breakpoint s
ite. Seventy-eight cases of CML were studied. Molecular analysis was perfor
med using the Southern blot technique. DNA was digested with Barn HI, Bg/II
, EcoRI, and XbaI. Hybridization was performed using the human 3' bcr (PR-1
) probe. BamHI and BglII could differentiate fragment 1 (F1) showing rearra
ngement (R) with Barn HI and germline configuration (G) with BglII; F2/3 sh
owing R with both, and F4 showing R with BamHI and G with BglII. F2/3 cases
were further divided by HindIII enzyme into F2 showing (G) and F3 shouing
(R). Fragment 0 showed G with both, but R with EcoRI and/or XbaI, while 3'
deletion gave G with all four enzymes. Our results showed a relative incide
nce of 6.4% for FB, 20.5% for F1. 32.1% for F2, 19.2% for F3, 15.4% For F4,
and 6.4% for 3' deletion. Sixty cases were evaluated clinically and hemato
logically and were followed up for disease evolution and survival. They inc
luded 32 cases in early chronic phase, 24 in late chronic phase, two in acc
eleration, and two in blastic crisis. No significant correlation was encoun
tered between the breakpoint site and any of the clinical and hematological
data except those patients with 3' deletion who showed a very short surviv
al. The study emphasizes Southern blotting as the method of choice for mole
cular characterization of CML and offers a simple and economic strategy for
diagnosis and determination of breakpoint fragment. (C) 2000 Elsevier Scie
nce Inc. All rights reserved.