多发性骨髓瘤（Multiple myeloma，MM）是严重威胁生命的血液系统恶性肿瘤，其发病机制仍不明确。PTP-PEST是酪氨酸磷酸酶家族的新成员，在造血细胞中广泛表达，可能与造血细胞的分化、发育、活化调控密切相关。近年来发现PTP-PEST能作为抑癌基因在许多肿瘤的发生、预后判断中发挥重要作用，但关于PTP-PEST在造血系统肿瘤尤其是MM发病中的作用尚不明确。本课题组的前期研究发现，PTP-PEST在MM患者骨髓标本和多种MM细胞株中表达明显降低，过表达PTP-PEST则能显著抑制MM细胞的增殖，进而提示PTP-PEST极有可能参与调控MM的发病。本研究拟通过过表达或干扰PTP-PEST，观察其对人MM细胞株增殖、凋亡、细胞周期、侵袭力、药物敏感性和体外成瘤能力的影响，以期初步阐明PTP-PEST在MM发病和耐药中的作用及机制，为临床上MM的治疗、预后判断提供新的干预靶点。

Multiple myeloma (MM) is a kind of hematological malignancy that causes great threat to life. However, the pathogenesis of MM remains unclear. PTP-PEST, as a new member of the protein tyrosine phosphatase family, is widely expressed in hematopoietic cells and regulates their differentiation, development and activation. In recent years, PTP-PEST is found to act as a tumor suppressor in many tumors, but the role of PTP-PEST in hematological malignancies, especially in the pathogenesis of MM is still obscure. Our preliminary results show that PTP-PEST expression is reduced in bone marrow samples from MM patients and a variety of MM cells lines. Overexpression of PTP-PEST could significantly inhibit the proliferation of MM cells, indicating PTP-PEST may be involved in the pathogenesis of MM. By overexpression or knock-down of PTP-PEST, the present study aims to explore the effect of PTP-PEST on the proliferation, apoptosis, cell cycle and drug sensitivity of MM cells, as well as their ability to form tumor in vitro. Our study will help to clarify the role and mechanism of PTP-PEST in MM pathogenesis, providing novel targets for the treatment and prognosis of MM.