| Objective:The enhancement of DNA repair ability is one of the reasons of adult patients with acute leukemia endureing primary or secondary drug resistance. Non-homologous end joining(NHEJ) plays a key role in Double-strand break (DSB)which consists of Ku70, Ku80 and DNA -PKcs. DNA-PKcs is catalylic subunit which is the most important factor in NHEJ. There is disputation on DNA-PKcs sensitivity in tumor radiation and chemotherapy. Some reports say high expression DNA-PKcs of the tumor is resistant radiation and chemotherapy, however, other say there is no relationship. At present, there is few report about DNA-PKcs in adult acute leukemia and whether DNA-PKcs become the prediction effect index in adult leukemia need to be studied further. Therefore, this study test the expression with clinical characteristics, chromosome abnormality and clinical effect to explore the significance of NHEJ this major repair way in acute leukemia.Methods:Indirect immune fluorescence spectrometry was used to test the expression of DNA-PKcs in bone marrow mononuclear cells of 105 patients with acute leukemia before chemotherapy and 41 of them after 2 period of treatment. Cytogenetic data were obtained from 26 of them by R band karyotypic analysis. Using the data SPSS 16.0 statistical software chi-square test, Fisher precisely the probability method and the rank converting non-parameter test, P< 0.05 showed a statistically significant.Results:1. DNA-PKcs and clinical characteristics The total positive expression in 105 cases is 53.3%. There is no obvious relation with median age, gender, median hemoglobin level and median platelets level, percentage of bone marrow blasts, clinical type (P=0.891 P=0.411,P=0.240,P=0.052,P=0.376,P=0.261). However, DNA-PKcs positive group had 17 cases (17/39) patients with more than 100×10^9/1WBC . Compareing negative group (5/44), there is a statistially significant different(P=0.011).2. DNA-PKcs and therapy effect In 62 cases before therapy, there are 33 patients with non-remission and 29 cases with remission. The positive expression of DNA-PKcs in non-remission group69.7% (23/33) was significantly higher than that remission group37.9%(11/29), P<0.05. After two cycles of chemotherapy, the positive expression of DNA-PKcs betreew non-remission group 73.7%(14/19)and remission group40.9%(9/22) has a statistically signi fic-ant difference, P<0.05. However, there is no statistically significant difference between before chemotherapy and after chemotherapy (Z=-0.551, P=0.593).3. DNA - PKcs and chromosomes There are 10 cases with chromosome abnormality 26 patients, accounting for 38.5%. There are 2 cases abnormal in t(15; 17)(q22 q21). The rest are del(7p), t(9;22) (q34;q11);t(9;22)(q34;q11),der(13),-20;-3;+22; -Y,t(8;21) (q22;q22); 7q-?,+ mar; 9q-; +6,+12/+7,+12each case. The positive of DNA-PKcs in chromosome abnormal group (7/10) was significantly higher than chromosome normal group (4/16), P<0.05.Conclusions:1.The increased DNA-PKcs protein expression had closely relationship with WBC count level.2.There is no obvious relation with median age, gender, percent-age of bone marrow blasts, clinical type , median hemoglobin level and median platelets level.3.There was a correlation between the expression of DNA -PKcs and karyotype and clinical prognosis in adult acute leukemia. |
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