Protein tyrosine phosphatase receptor-typeγ (PTPRG) is down regulated in CML patients at diagnosis and restored upon TKI treatment: Preliminary results

Background. Chronic myelogenous leukemia (CML) is the most common myeloproliferative disease accounting for ∼15% to 20% of all cases of leukemia (1-1.5/100.000 cases per year). It originates from a pluripotent bone marrow stem cell in which a t(9;22) results in the production of BCR/ABL fusion protein which has a constitutive tyrosine kinase activity and deregulates signal transduction pathways. Phosphorylation of key residues is required for the full transforming activity of BCR/ABL; for this reason much attention has been focused on the role of phosphatases, natural regulators of the tyrosine kinase signaling. We have previously reported that protein tyrosine phosphatase receptor type γ (PTPRG) is a tumor suppressor gene which interacts with BCR/ABL, inhibits downstream signaling events and is downregulated in CML. Whitin the QNRF research project NPRP 4-157-3-052 we analyzed the expression levels of PTPRG gene in 32 CML patients at diagnosis and following TKI treatment aiming at the evaluation of the c...