Elevated PIM2 gene expression is associated with poor survival of patients with acute myeloid leukemia.

The PIM2 gene encodes the serine/threonine kinase involved in cell survival and apoptosis. The aim of the study was to evaluate the expression of the PIM2 gene in acute myeloid leukemia (AML) and to examine its role in apoptosis of the blastic cells. We analyzed the PIM2 expression in 148 patients: 91 with AML, 57 with acute lymphoblastic leukemia and 24 healthy controls by Real-Time PCR and Western blot. Inhibition of the PIM2 gene in human leukemic HL60 cell line was performed with RNAi and apoptosis rate was analyzed. Our results indicate that overexpression of PIM2 in AML is associated with low complete remission rate, high-risk cytogenetics, shorter leukemia-free survival, and event-free survival. Cytometric analysis of HL60/PAC-GFP and HL60/PAC-GFP-shPIM2 cells revealed an increase in the number of apoptotic cells after inhibition of PIM2 gene. In summary, the elevated expression of PIM2 in blastic cells is associated with poor prognosis of AML patients and their resistance to induction therapy.