Expression and distribution of PPP2R5C gene in leukemia

Background: Recently, we clarified at the molecular level novel chromosomal translocation t(14;14)(q11;q32) in a case of Sezary syndrome, which caused a rearrangement from TRAJ7 to the PPP2R5C gene. PPP2R5C is one of the regulatory B subunits of protein phosphatase 2A (PP2A). It plays a crucial role in cell proliferation, differentiation, and transformation. To characterize the expression and distribution of five different transcript variants of the PPP2R5C gene in leukemia, we analyzed the expression level of PPP2R5C in peripheral blood mononuclear cells from 77 patients with de novo leukemia, 26 patients with leukemia in complete remission (CR), and 20 healthy individuals by real-time PCR and identified the different variants of PPP2R5C by RT-PCR. Findings: Significantly higher expression of PPP2R5C was found in AML, CML, T-ALL, and B-CLL groups in comparison with healthy controls. High expression of PPP2R5C was detected in the B-ALL group; however, no significant difference was found compared with the healthy group. The expression level of PPP2R5C in the CML-CR group decreased significantly compared with that in the de novo CML group and was not significantly different from the level in the healthy group. By using different primer pairs that covered different exons, five transcript variants of PPP2R5C could be identified. All variants could be detected in healthy samples as well as in all the leukemia samples, and similar frequencies and distributions of PPP2R5C were indicated. Conclusions: Overexpression of PPP2R5C in T-cell malignancy as well as in myeloid leukemia cells might relate to its proliferation and differentiation. Investigation of the effect of target inhibition of this gene might be beneficial to further characterization of molecular mechanisms and targeted therapy in leukemia.