Evaluation of O6-Methylguanine DNA Methyltransferase Activity in Patients With Gastric Cancer
O6-Methylguanine DNA methyltransferase (O6-MGMT) reverses DNA alkylation damage produced by alkylating agents. O6-MGMT is also a major determinant of cellular resistance to adjuvant chemotherapy with alkylating drugs. O6-MGMT activity was measured in samples from patients with gastric cancer, including tumor, adjacent normal appearing mucosa, and peripheral blood leukocytes (PBL). O6-MGMT activity of PBL from healthy individuals was evaluated as control. There was no significant difference between controls and patients for O6-MGMT activity in PBL. O6-MGMT activity was significantly increased in tumor tissue. Tumor O6-MGMT activity was found to be independent from tumor subgroups and tumor grade. A positive correlation was determined between O6-MGMT activity in tumor and in circulating PBL. The results indicate that O6-MGMT, a defense protein against alkylating agent-mediated carcinogenesis, increased in gastric tumors. This may explain the low response rate to drug combinations, including chloroethylnitrosoureas, exhibited by patients with gastric cancer.
Document Type: Research Article
Affiliations: 1: *Department of Biochemistry, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, 34300-Turkey 2: †Department of General Surgery, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, 34300-Turkey 3: ‡Department of Biophysics, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, 34300-Turkey 4: §Department of Pathology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, 34300-Turkey
Publication date: 2002-01-01
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