[The expression of O6-methylguanine DNA methyltransferase and p53 in non-small cell lung cancer and the association with the prognosis].

To investigate the expression and role of O(6)-methylguanine DNA methyltransferase (MGMT) and p53 in non-small cell lung cancer (NSCLC) and the association with prognosis. Immunohistochemical method was used to investigate the expression of MGMT and p53 in NSCLC specimens from 110 cases and in 20 cases of benign lung diseases as the control. The association of their expression with the prognosis of the 110 patients was evaluated. The positive expression of MGMT in NSCLC and benign lung diseases was 41.8% (46/110) and 80% (16/20) (χ(2) = 9.89, P < 0.05), respectively. The positive expression of p53 in NSCLC and benign lung diseases were 56.4% (62/110) and 0% (0/20) (χ(2) = 21.551, P < 0.05), respectively. There was a significant association between expression of MGMT with smoking, and lymph node metastasis (χ(2) = 12.107, P < 0.05; χ(2) = 6.512P < 0.05). There was also a significant association between expression of p53 with smoking and lymph node metastasis (χ(2) = 6.330, P < 0.05; χ(2) = 7.909, P < 0.05). A negative correlation was observed between the expression of MGMT and that of p53 protein in NSCLC (R(S) = -0.592, P < 0.05). The 5-year survival rate and median survival time of 110 cases was 10.9% (12/110), and (30.4 ± 0.6) months. In 46 cases with positive expression of MGMT the 5-year survival rate was 0% (0/110) and median survival was (25.9 ± 0.4) months, which were lower than those in the 64 patients with negative expression of MGMT [18.8% (12/64), (32.4 ± 0.7) months], Log rank test χ(2) = 23.569, P < 0.05. In the 62 patients with positive expression of p53, the 5-year survival rate and median survival were 4.8% (3/62) and (30.4 ± 1.2) months, which were lower than those in the 48 cases with negative expression of p53 [18.8% (9/48), (30.5 ± 1.1) months], Log rank test χ(2) = 5.521, P < 0.05. The loss of expression of MGMT may lead to activation of the wild-type p53. They may participate in lung carcinomatosis, and may predict prognosis in patients with NSCLC.