MDM2 polymorphism, survival, and histology in early-stage non-small-cell lung cancer.

PURPOSE: MDM2 is a negative regulator of p53. The MDM2 309T/G polymorphism has been associated with differential MDM2 expression levels and inhibition of the p53 pathway. We hypothesized that the MDM2 G/G genotype may be associated with worse survival outcomes in lung cancer, especially in squamous cell cancers where p53 abnormalities are more common. PATIENTS AND METHODS: We evaluated the relationship between MDM2 polymorphism status and overall survival (OS) among patients with early-stage non-small-cell lung cancer (NSCLC) treated with surgical resection at Massachusetts General Hospital from 1992 to 2000. Kaplan-Meier methods and the log-rank test were used to compare survival by polymorphism status. Cox proportional hazards models were used to adjust for possible confounding variables.
RESULTS: There were 383 patients in the analysis. In the early-stage population as a whole, the G/G genotype seemed to be associated with worse OS on adjusted analysis (adjusted hazard ratio = 1.57; 95% CI, 1.03 to 2.40; P = .04). Among patients with squamous histology, OS was significantly worse among those with the G/G genotype (P = .0001 by log-rank test), with 5-year survival rates among the genotypes of 59% for T/T, 53% for T/G, and 7% for G/G.
CONCLUSION: Our findings suggest that the G/G genotype of the MDM2 polymorphism is associated with worse OS among early-stage NSCLC patients, particularly those with squamous cell histology.