Expression And Correlation Of MGMT, MCM2 And Caspase-3 In Human Gliomas

Objective To investigate the expression of O6-methylguanine-DNA-methyltransferas (MGMT), Minichromosome maintenance 2 (MCM2), Cysteinyl aspartate specific protease-3 (Caspase-3) in human glioma, and to analyze the clinical pathological significance and the correlation of the expression of MGMT and MCM2, Caspase-3 in gliomas of different pathological grading, different tissue typing and different locations.Methods According to The 2007 WHO Classification of Tumours of the Central Nervous System, a total of 58 cases of paraffin-embedded glioma tissue were classified and used to detect the expression of O6-methylguanine-DNA-methyltransferas (MGMT), Minichromosome maintenance 2 (MCM2), Cysteinyl aspartate specific protease-3 (Caspase-3) by immuno-histochemical technique (IHCT) streptavidin-perosidase (SP) method, including 14 cases of WHO GradeⅠtumors (9 cases of Pilocytic astrocytoma,5 cases of Astrocytoma),15 cases of WHO GradeⅡtumors (7 cases of Astrocytoma,1 case of Diffuse astrocytoma,1 case of Oligodendroglioma,3 cases of Oligoastrocytoma,2 cases of Ependymoma,1 case of Pleomorphic xanthoastrocytoma),15 cases of WHO GradeⅢtumors (1 case of Astrocytoma,4 cases of Anaplastic astrocytoma,1 case of Oligoastrocytoma,2 cases of Anaplastic oligoastrocytoma,3 cases of Anaplastic oligodendroglioma,2 cases of Anaplastic ependymoma,2 cases of Glioblastoma),14 cases of WHO Grade IV tumors (12 cases of Glioblastoma,2 case of Medulloblastoma), and analyze the results with the Image Pro Plus software.Results1. MGMT, MCM2 and Caspase-3 protein expressed positive in various degree among different grades of glioma sample. With the increasing of pathological grade, the mean density of MGMT, MCM2 and Caspase-3 also increased. The mean density in different grades are:MGMT: WHO GradeⅠ54.36±11.4, WHO GradeⅡ303.29±87.97, WHO GradeⅢ528.51±60.34, WHO Grade IV 733.60±192.02; MCM2:WHO GradeⅠ84.58±47.79, WHO GradeⅡ419.28±93.14, WHO GradeⅢ686.26±99.36, WHO GradeⅣ832.43±120.81; Caspase-3:WHO GradeⅠ33.39±13.42, WHO GradeⅡ373.72±140.22, WHO GradeⅢ598.52±152.19, WHO GradeⅣ814.58±150.77 respectively. The expression of MGMT, MCM2 and Caspase-3 protein correlated well with each other (MGMT vs MCM2:r=0.854, P=0.000, MGMT vs Caspase-3:r=0.812, P=0.000, MCM2 vs Caspase-3:r=0.843, P=0.000).2. The expression of MGMT, MCM2 and Caspase-3 were significantly different in pairwise comparison of every two grades of results among all of them(P<0.05). And they are correlated well with pathological grades (MGMT:rs=0.902, P=0.000, MCM2:rs=0.918, P=0.000, Caspase-3: rs=0.815, P=0.000).3. MGMT, MCM2 and Caspase-3 protein expressed positive in various degree among different tissue typing of glioma sample. The expression of MGMT, MCM2 and Caspase-3 were significantly different in pairwise comparison of some tissue types among all of them, especially, the expression of all three of them are higher in astrocytic tumors, oligo/oligoastrocytic tumors and Ependymal tumors than in glioblastomas and embryonal tumors (P<0.05), the expressions of MCM2 and Caspase-3 are lower in ependymal tumors than those in embryonal tumors (P<0.05).4. MGMT, MCM2 and Caspase-3 protein expressed positive in various degree among different locations of glioma sample. The expression of MCM2 and Caspase-3 were significantly different in pairwise comparison of only some of the locations among all of them, especially, the expression of ventricular system are higher than those in other regions (P<0.05).Conclusion The expression level of MGMT, MCM2 and Caspase-3 protein are bound up with the different pathological grading, significantly different in pairwise comparison of only some of the tissue typing and only MCM2, Caspase-3 in pairwise comparison of only some of the locations of glioma samples. They are not correlated with each other by pathological grading. They probably promotes the tumorigenesis and progression of human gliomas. The combined detection of MGMT, MCM2 and Caspase-3 proteins is valuable for prediction of malignancy, prognosis and chemosensitivity of human gliomas, thus also for providing experimental evidence for the development of a reasonable and comprehensive treatment of human glioma.