Detection of cytogenetics abnormalities in chronic lymphocytic leukemia using FISH technique and their prognostic impact

ABSTRACT

Chronic lymphocytic leukemia [CLL] is a clonal lymphoproliferative disorder characterized by progressive accumulation of morphologically and immunophenotypically mature lymphocytes. Characterization of genomic aberrations may help to understand the pathogenesis of CLL and may give prognostic information independent from conventional clinical markers for a risk-adapted management of CLL patients. The aim of the present study is to determine the most common cytogenetics abnormalities between patients with CLL and its prognostic impact. The present study was carried out on 20 adult patients presented with chronic lymphocytic leukemia. The patients were diagnosed on the basis of standard clinical [lymph node involvement and/or hepatosplenomegaly], hematological and immunophenotypic criteria for diagnosis of B-CLL. All cases were studied at the time of their diagnosis. FISH technique was successfully performed on PB samples using CLL LSI probes for ATM [11q22] / GLI [12q13] and 13q14/ p53 [17pl3]. For comparative statistical studies, the patients were divided into group I [patients with favorable outcome] and group II [patients with unfavorable outcome]. All patients showed one or more cytogenetic abnormality with the prevalence of p53 in 16 patients out of 20 that perfectly correlated with the poor outcome of the patients. This is followed by deletion in the 13q14 and to a lesser extent deletion in ATM gene, but no one has exhibited amplification in the 12q13 locus. p53 deletion as a sole abnormality has a higher prognostic power than other cytogenetics abnormalities. The cytogenetics study using FISH panel for CLL patients in a complementary fashion to the other clinical and laboratory findings may overcome the pitfalls in the diagnosis and may also assess the assignment of therapeutic protocols for CLL patients according to the results of their cytogenetic analysis at the time of diagnosis