O6-methylguanine-dna methyltransferase activity and sensitivity of 20 chinese tumor cell strains to l-(4-amino-2-methyl-5-pyrimidinyl) methyl-3- (2-chloroethyl)-3-nitrosourea

O6-methylguanine-DNA methyltransferase (MGMT) plays an important role in repairing alkylated DNA. MGMT activity as well as cellular sensitivity to 1- ( 4- amino- 2-methyl - 5 - pyrlmidinyl) methyl - 3 - (2 - chloroethyl) - 3 -nitrosourea (ACNU) of 20 Chinese tumor cell strains were assayed. A linear response between MGMT activity and ACNU sensitivity (D10) was observed. The lower the MGMT activity in the cells, the more the sensitivity to ACNU killing. It suggested that assay of MGMT activity in tumor biopsy could be used as a guide to predict the effectiveness of ACNU treatment in chemotherapy of human cancer.