Investigation of 13q14.3 deletion by cytogenetic analysis and FISH technique and miRNA-15a and miRNA-16-1 by real time PCR in chronic lymphocytic leukemia

Background: The most frequent cytogenetic aberration is 13q14.3 deletion in Chronic Lymphocytic Leukemia (CLL). HsamiR-15a/hsa-miR-16-1 are tumor suppressor miRNAs encoded from 13q14.3 region.

Objectives: The aim of this study was to investigate the 13q14.3 deletion using molecular and cytogenetic techniques and association with miRNA-15a/miRNA-16-1.

Materials and methods: We used peripheral blood samples of 30 CLL patients who were either induced and or non-induced with DSP30+IL-2 to determine 13q14.3 deletion by karyotyping and iFISH. Expression levels of hsa-miR-15a/miR-16-1 were measured using qRT PCR and compared with deletions.

Results: 13q14.3 deletion was detected in 8.6% of cases by karyotyping and in 65% by iFISH. Mosaic forms (monoallelic+biallelic) were observed in 50% of cases. Besides determining common chromosome abnormalities such as add(2)(q37), t(2;7) (p11.2;q22), del(6)(q13q21), del(6)(q25), add(9)(q21), del(11)(q23), t(11;14)(q13;q32), del(13)(q11q12), del(13)(q12q14), add(14) (q23), del(14)(q23), t(14;19)(q32;q13.1), del(15)(q23), del(17)(p12), t(18;22)(q21;q11.2), add(21)(p13) and t(17;21)(q11.2;122), we also determined t(1;13)(q32;q34), inv(2)(p25q21), del(13)(q22q32), t(14;19)(q24;q13), dup(17)(q21q23), der(21;21)(p13;p13) which have not been reported previously. Mitotic index data was found statistically significant and DSP30+IL-2 increased mitotic index by 2.5 folds. Association between decreased miR-16-1 expression and deletions was statistically significant.

Conclusion: We suggest that cytogenetic and iFISH analyses are complementary and use of DSP30+IL-2 is effective .in CLL. Decreased expression of hsa-miR-16-1 is remarkable.