While the T/T+G/T genotype of RRM1 ‐585T>G was associated with a decreased risk for tumorigenesis, suggesting that these SNPs may have potential function to influence the amplification and expression of RRM1. Subgroup analysis was also conducted, and polymorphisms of RRM1were both associated with NSCLC and SCLC. Here, RRM1 is linked to small cell lung carcinoma.