Karyotypic and Molecular Genetic studies in Indian Patients with Chronic Lymphocytic Leukemia

Abstract

This work was undertaken to collect cytogenetic and molecular genetic data on Indian patients with CLL. A total of 20 patients were included in this study. Of the 20 patients, 85% were males and 50% females, with a predominance in the age group 61-65 years. Cytogenetics was performed on all the samples at diag-not-3is and during the course of the disease. Karyotype was successful in 75% of the patients, 30% showed a normal karyotype and 45% clonal aberrations. Trisomy 12 was seen in 20%, 10% had aberrations involving chromosome 14 and other aberrations 15%. Karyotype evolution was seen in 2 patients, of which one showed progressive disease. All the samples were analysed for +12 and RB-I deletion by FISH. 40% of the cases had +12 [an increase of 20% over conventional cytogenetics] and 25% has monoallelic RB-I deletion. Southern Blot Analysis was performed to look for the rearrangements of IgH, TCRand#946;, bc1-1 and bc1-2 genes. All the cases of CLL showed Ig JH rearrangements and none of them had TCRand#946; involvement, indicating B-cell origin of these cancers. One patient had bcl-1 rearrangement within the MTC. Two patients showed rearrangement of bc1-2 within the mbr region.Although the period of observation was too short to reach any conclusion we did not find any distinctive features in Indian patients with CLL, except for the more involvement of mbr region of the bcl-2 gene. There seems to be no difference in the pathobiology and clinical manifestations of Indian CLL patient and that in western countries. The low incidence of CLL in Asian countries might be due to racial and geographical difference. Further studies like HL A and other genetic markers which are race specific should be carried out to explain the low incidence of CU in Asian countries. newline