Fluorescence in Situ Hybridization for Detecting Molecular Cytogenetic Abnormalities of Chronic Lymphocytic Leukemia

OBJECTIVE To investigate the value of fluorescence in situ hybridization (FISH) in the diagnosis and prognosis evaluation of patients with chronic lymphocytic leukemia (CLL). METHODS Ninty-three patients with newly diagnosed CLL were tested by five probes including RB1 (13q14.1), D13S25 (13q14.3), p53(17p13.1), ATM( 11q22.3) and CSP12, while conventional cytogenetics (CC) was used for karyotype analysis. Then the correlation of the molecular cytogenetic abnormalities with the clinical Binet stages, Rai stages and the other related laboratory examinations was analyzed. RESULTS The detection rate of chromosome abnormality in 93 patients was 79.6%, out of which detection rate of 13q (13q- was the highest and accounted for 45.2%), followed by trisomy 12 (+12) 26.9%, p53 deletion (17p-) 19.4% and ATM deletion (11p-) 17.2%. There were 27 cases (29.0%) with 2 or more abnormalities, including 13 cases with 13q-/17q-, 5 with 13q-/11q-, and 4 with 13q-/+12. Compared with CC test results, the positive rate of FISH detection was significantly higher (χ2=32.127, P＜0.01). There was no significant correlation between FISH results and Rai stages (P＞0.05), meanwhile 17p- highly correlated with later stage of the Binet stages (P=0.012). The molecular cytogenetic abnormalities significantly correlated with age, absolute value of peripheral lymphocyte count and CD38 expression level (P＞0.05). The incidence of 13q- in female (65.4%) was statistically significantly higher than that in male (37.3%) (P=0.015). The unmutated IGHV rate of CLL patients with a 17p- was significantly higher than that in patients without this genetic abnormality (P=0.013). The expression of CD38 was detected among 29.0% of the patients, which significantly correlated with Binet stages (P=0.027) and unmutated IGHV (P=0.006). CONCLUSION FISH can greatly increase the detection rate of molecular cytogenetic abnormalities in CLL patients, which, as a powerful supplement to the conventional cytogenetics, can be applied for the clinical staging and prognosis evaluation of CLL patients.