Expression Of COX-2 In Acute Leukemia And Its Relationship With Bcl-2

Objective: Acute leukemia (AL)is the most common malignant disease of hematology . The features of leukemia are suppression of normal hematopoiesis by blast cells of a clone arising from malignant transformation of hematopoietic stem cell and organ infiltration .Until now , the concrete cause of mechanism of malignant transformation and metastasis has remained poorly understood .At present many researches suggest that cyclooxygenase-2 ( COX-2) be closely associated with tumor .COX is the key enzyme in the process of converting arachidomic acid(AA) to prostaglandin ( PG) .There are two isoenzyme of COX that is COX-1 and COX-2 .They have different biological functions. COX-1 is a structural enzyme which appears in allkinds of tissues .COX-2 doesn' t express in many tissues under normal condition , but can be induced by many factors such as tumor necrosis factor . Seldom reports documented the relationship between COX-2 and leukemia .In order to investigate the relationship between COX-2 and leukemia , our study examined the expression of COX-2 and Bcl-2 in bone marrow cells of untreated acute leukemia -, complete remission (CR) stage of acute leukemia and normal control by using immunocytochemical method .Materials and method: (1) Subjects were divided into three groups:?The untreated AL group (n=45,Male 25, Female 20, Mean age 35. 6Y) including acute lymphocytic leukemia (ALL) 15 cases and acute myelogenous leukemia (AML) 30 cases , According to the diagnostic standard worked out by FAB in 1985, AML were further subdivided into M2 12 cases, M3 7 cases, M4 6 cases, M5 5 cases. (D The complete remission stage of AL group (n=24, Male 14 , Female 10, Mean age 31. 2Y) including ALL 10 cases , AML 14 cases .According to the diagnostic standard worked out by Suzhou meeting in 1987, AML were further subdivided into M2 5 cases , M3 5 cases, M5 4 cases. (3) The normal control group (n=20,Male 12, Female 8, Mean age 30. 2Y) . (2) Col lecting the mononuclear cells of bone marrow of all subjects , test the positive rate of COX-2 and Bcl-2 by using immunocytochemical method. (Count 200 cells and the positive cell to gain the positive rate and score ). (3) The results were analyzed with chi-square test by SPSS10. 0, and we established the standard of statistic significance as a =0. 05.Results: (1) The positive rate and score of COX-2 in these three groups are : ( 54. 33 1 1. 18 ) % . 142.91 17. 40 ; (37.04 11.98) %, 70.46+11.01 and (32.25 8.54) %, 64.35 + 10.28 . The positive rate of COX-2 in patients with newly diagnosed untreated AL is significantly higher than that of complete remission stage of AL and the normal control group (P<0.05). There is no significant difference between the complete remission group and the normal control group (P>0.05). (2) The positive rate and score of Bcl-2 in these three groups are (52.51 + 10.20) %, 142.91 + 17.40; (31.50 + 9.46) %, 65.17 + 10. 45 and (28. 55 + 8. 65) %, 59. 05 + 12. 52. The positive rate of Bcl-2 in patients with newly diagnosed untreated AL is significantly higher than that of complete remission stage of AL and the normal control group (P<0. 05).There is no significant difference between the complete remission group and the normal control group (P>0.05). (3) There is positive relation between COX-2 and Bcl-2 in three groups .Conclusion : COX-2 and Bcl-2 overexpress in untreated acute leukemia group and the positive rate is significantly higher than those in complete remission stage of acute leukemia and the normal control group. It shows that the overexpression of COX-2 and Bcl-2 were a early event in acute leukemia .COX-2 may play an important role during the proliferation and the malignant transformation of leukemic cells. There is positive relation between COX-2 and Bcl-2 . Bcl-2 is an anti-apoptosis gene .COX-2 can upregulate the expression of Bcl-2 .