Furthermore, significant higher risk associated with GG genotype of MDM2 SNP309 polymorphism among the p53 mutation-positive subgroup have been found in lung cancer [40] and gastric cancer [41], showing that SNP309 G allele could accelerate tumor formation and cause the occurrence of multiple primary tumors in a lifetime for P53 mutation carriers [9,38]. Here, MDM2 is linked to lung carcinoma.