The Expression Of Cyclin Kinase Inhibitor P21～(WAF1) And P27～(KIP1) In The Leukemia Cells Fromthe Pediatric Patients With Acute Leukemia

Objective: Cell cycle is the fundamental process of all cells. The cells go through proliferation, differentiation, apolexis and death with the cell cycle going on. The disorders of cell cycle of eukaryote are the reasons for the ultra- proliferating and carcinomatous. In recent years, researchers have made great improvement in the studies of cell cycle. The role of cyclins, cyclin dependent kinase (CDK) and cyclin kinase inhibitor (CKI) have been founded. The cell cycle is driven by the activating of CDK. Cyclins can enhance the process but CKIs slow down the process by inhibiting the activation of CDK. CKIs are divided into two categories. One is INK4 which inhibits the activation of CDK4-CyclinD1 and CDK6-CyclinD1.The other one is KIP which inhibits the activation of many complicated CDK-Cyclins. P21WAF1,P27KIP1 are the members of CKI family. There are eighty conservativeamino acid sequences that have the similarity in their structure and function. Methods: Normally, P21WAF1,P27KIP1are expressed in most of eukaryote cells and always regulates cell cycle in quantity. Previous studies have indicated the abnormal expression of these two proteins in some entity neoplasias including adult leukemia. In this study, the expression of P21WAF1 and P27KIP1 were detected in the children with acute leukemia. The clinical significance was analyzed. The method of immunocytochemistry is used to estimate the expression of P21WAF1 and P27KIP1. Some of patients were followed -up after the remission of the leukemia. Both positive percentage and intensity of the cells were counted. Results:Our results showed that the positive ratios of P21WAF1 in total samples, ALL samples and AML samples are 12.5%(4/32),9.1%(2/22)and 20%(2/10)respectively and the positive ratios of P27KIP1 are 40.6%(13/32),50%(11/22)and 40 %(4/10). Follow up several patients with acute leukemia, the trends of higher expression of P21WAF1 and P27KIP1 were noted. Most of the P27KIP1positive cells are pigmented in nucleus in the control group while pigmented in both nucleus and plasma in the studied patients. Conclusion: The study indicated that P21WAF1and P27KIP1 have lower expression in the pediatric patients with leukemia, which maycontribute to the pathogenesis and the progress of the leukemia. The follow-up study also suggests that P21WAF1,P27KIP1 may be a marker for the evaluation of the disease and the effect of the treatment.