EXPRESSION OF LIPOPROTEIN LIPASE AND c-MYC ONCOGENE IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA AFFECTED BY THE CHORNOBYL ACCIDENT

Abstract

Objective. to determine the association between the expression of lipoprotein lipase (LPL) and c-MYC genes in peripheral blood cells of chronic lymphocytic leukemia (CLL) patients affected by the Chornobyl catastrophe depending on the mutational status of IGHV genes. Methods. Analysis was performed in the group of 69 CLL patients irradiated due to the Chornobyl NPP accident (58 clean-up workers of 1986 year, 6 inhabitants of radionuclide contaminated areas, and 5 evacuees). The IGHV gene mutational status was studied by polymerase chain reaction (PCR) followed by direct sequencing. LPL and c-MYC expression was evaluated by Quantitative Real-time PCR. Data were analyzed with the SPSS software package, version 20.0. Results. Relative LPL expression levels in CLL samples ranged from 0 to 1663.5 (mean 138.47 ± 30.69, median 26.1). A strong correlation between individual LPL expression levels and IGHV mutational status was found (r = 0.684; p < 0.0001). The average relative c-MYC expression level was 5.7 ± 0.87 (median 2.86; range 0–48.5). No association between c-MYC expression and IGHV mutational status was found. Among unmutated IGHV cases, a correlation between LPL and c-MYC gene expression levels was identified: r = 0.351; p = 0.013. Conclusions. Our data confirm the dominant concept that unmutated IGHV CLL cases are more sensitive to the action of proliferative stimuli compared to mutated IGHV CLL cases. This is manifested by an increase in the expression of a functionally significant LPL gene, is one for the strongest negative prognostic markers in CLL. Key words: lymphocytic leukemia, LPL, c-MYC, IGHV genes, Chornobyl NPP accident.