Evaluation of O-6-methylguanine DNA methyltransferase activity in patients with gastric cancer

Dincer Y. , Akcay T. , Tortum O. , Alademir Z., Onen S., Dogusoy G.

ONCOLOGY RESEARCH, cilt.13, sa.4, ss.205-209, 2003 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 13 Konu: 4
  • Basım Tarihi: 2003
  • Sayfa Sayıları: ss.205-209


O-6-Methylguanine DNA methyltransferase (O-6-MGMT) reverses DNA alkylation damage produced by alkylating agents. O-6-MGMT is also a major determinant of cellular resistance to adjuvant chemotherapy with alkylating drugs. O-6-MGMT activity was measured in samples from patients with gastric cancer, including tumor, adjacent normal appearing mucosa, and peripheral blood leukocytes (PBL). O-6-MGMT activity of PBL from healthy individuals was evaluated as control. There was no significant difference between controls and patients for O-6-MGMT activity in PBL. O-6-MGMT activity was significantly increased in tumor tissue. Tumor O-6-MGMT activity was found to be independent from tumor subgroups and tumor grade. A positive correlation was determined between O-6-MGMT activity in tumor and in circulating PBL. The results indicate that O-6-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.