Multivariate analysis using Cox-regression analysis showed that, for patients with NSCLC treated with first-line gemcitabine and carboplatin combination chemotherapy, RRM1 gene expression in peripheral blood may be a predictor of survival and tumor susceptibility to chemotherapy (HR 2.574, 95% CI 0.886–7.479, P = 0.082; Table 3). Here, RRM1 is linked to non-small cell lung carcinoma.