Expression of the PIM2 gene is associated with more aggressive clinical course in patients with chronic lymphocytic leukemia.

Background. The PIM2 gene belongs to the PIM family, which encodes serine/threonine kinases involved in cell survival and apoptosis. The relation between the expression of the PIM2 gene and the course of chronic lymphocytic leukemia (CLL) has not been fully determined. Objectives. The aim of the study was to evaluate the role of the PIM2 gene as a marker of CLL malignancy and its importance as a predictive and prognostic factor. Material and methods. Sixty-seven patients, 35 females and 32 males, aged 49-90 years, with de novo CLL, and 14 healthy individuals were enrolled in the study. Expression of the PIM2 gene was analyzed using TaqMan RQ-PCR assay and western blot test. Results. Median PIM2 gene expression in CLL patients was higher than in controls. Patients with high expression of the PIM2 gene had shorter progression-free survival and time to first treatment than patients with low PIM2 expression. It was found that patients with CR had lower expression of the PIM2 gene than patients without complete remission (CR). Notably, associations between high PIM2 expression and rapid lymphocyte doubling time, the percentage of malignant lymphocytes with ZAP70 expression and the Rai stage were revealed. Conclusions. We found that the PIM2 gene is associated with a more aggressive clinical course of CLL.