DETECTION OF MONOSOMY 7 IN ACUTE MYELOID LEUKEMIA BY CONVENTIONAL CYTOGENETICS AND FLUORESCENCE IN SITU HYBRIDIZATION (FISH) TECHNIQUE

Abstract

The karyotype ofleukemia blasts has emerged as one of the most important diagnostic and prognostic investigations in acute myeloid leukemia (AML). It has been reported that the association of routine cytogenetics (RC) and molecular techniques like fluorescent in situ hybridization ( FISH ) provides promissing tool in detection of cytogenetic changes in both metaphase and interphase. So this work aimed to detect monosomy 7 in AML patients by RC and FISH technique. Peripheral blood (PB) or bone marrow (BM) aspirate were obtained from 32 patients (30 newly diagnosed and 2 CML in blastic crisis). Patient's age ranged from 5-55 years (median 38 years), M:F 1:1. Two healthy subjects were included as control for interphase FISH. All patients were subjected to complete blood picture, BM and PB examination, cytochemistry, immuno-phenotyping, RC by G­ banding and FISH using centromeric probe for chromosome 7 (CEP 7) .In addition patients were followed up for 6-18 months as regards complete remission (CR) and relapse (R). Successful karyotyping was encountered in 30/32 (93.8%) patients with failed mitosis in 2/30 (6.3%). Out of the 30 successful karyotypes, 4 (13.3%) cases had normal karyotypes and achieved CR. The remaining patients were classified as: 5 (16.7%) patients with chromosomal abnormalities restricted to AML [t(l5;17), inv(16), t(8;21), and llq23 rearrangements]. 13 (43.3%) with chromosomal abnormalities restricted to myeloid lineage but not characteristics to AML [complete monosomy or.partial deletion of the long arm of ch. 5 or 7, translocation involving ch. 7, +8, t(6;9), rearrangement of 3q21-3q216 and deletion oflong arm of ch. 9].3(10%) Ph+ positive AML cases (l de novo that died prior chemotherapy and 2 CML in blastic crisis that showed IR and finally died) and 5 (16.7%) complex karyotype (1 pseudodiploidy and 4 with different abnormalities affecting many chromosomes).