Leukemias are characterized by a maturation arrest of the malignant clone , with accumulation of immature cells and inhibition of normal hematopoiesis . for lymphocytic leukemia , immunophenotyping plays a central role in defining clinically relevant subsets 人体是由细胞组成的，细胞正常结构和功能的异常，必然导致细胞乃至人体各组织器官的结构和功能的紊乱，并由此引起疾病。
In drosophlia notch is typically involved in binary cell fate decisions including neurogenesis , myogenesis and hematopoiesis . in mammals , notch regulates development of hematopoietic system , muscle , pancreas , and many other tissures 在果蝇的神经、肌肉、卵子发生中， notch信号途径参与它们的发育过程，在哺乳动物中notch信号途径调节造血系统、神经、肌肉、胰腺、血管和其他一些组织的发育。
Chemotaxis mediated by chemokine receptors , such as cxcr4 , play a key role in lymphocyte homing and hematopoiesis as well as in breast cancer metastasis . we have previously demonstrated that ? - arrestin2 functions to attenuate cxcr4 - meidated g protein activation and to enhance cxcr4 internalization . here we further show that expression of ( - arrestin2 in both hela and hek293 cells significantly enhanced the chemotactic efficacy of stromal - cell derived factor 1 ( ( sdf - 1 ( ) , the specific agonist of cxcr4 - arrestin2是趋化因子受体的一种重要的调节蛋白，本研究工作发现在hek - 293或hela细胞中升高- arrestin2的表达水平会显著增强cxcr4介导的趋化作用，反之当- arrestin2的表达被它的反义核苷酸或rnai所抑制， cxcr4介导的趋化作用则被明显抑制。
