PTEN and neoplasm: Although previous studies showed that a close correlation was found between the low expression of PTEN and the poor prognosis in some tumor patients including hematological malignancies [6,14,17,18] and the loss of PTEN gene disturbed the maintenance of quiescent HSCs and promoted leukemogenesis in mice [19], the exact mechanism of hypo-expression of PTEN in human leukemogenesis was not clear.