The association of patients’ characteristics and WEE1 polymorphisms with overall survival was explored by univariate Cox’s regression analysis in all 663 patients treated with platinum-based doublet chemotherapy (Table 1). The 4 WEE1 tag SNPs were classified by models including genotypic, dominant, recessive, or additive. Gender, smoking history, clinical stage, and histology were significantly associated with OS but no correlation was found with age, ECOG PS, or chemotherapy regimens. Using WEE1 genotypes as categorical variables, only rs3910384 in the 4 tag SNPs presented a statistically significant association with OS (p = 0.022). The dominant model of rs3910384 (p = 0.006), recessive model of rs3829254 (p = 0.022), and additive model of rs3910384 (p = 0.009), rs3829254 (p = 0.023), or rs4370932 (p = 0.028) showed statistically significant association. Furthermore, we included gender, smoking, clinical stage, histology, the rs3910384 dominant model, the rs3829254 recessive model, and the rs4370932 additive model in the multivariate Cox’s regression analysis. The results suggested that clinical stage (p = 8.0E-3), histology (p = 4.3E-4) and the rs3910384 dominant model (p = 4.0E-3) were independent predictive factors for OS (Table 2).Patients with the rs3910384 G/G genotype (mOS, 20.4; 95%CI, 17.6–23.2) had higher median OS (mOS) than A/G+A/A (mOS, 16.9; 95%CI, 15.1–18.7; p = 4.0E-3) in all 663 patients treated with platinum-based doublet regimens. The Kaplan-Meier curves of OS according to polymorphisms of the WEE1 tag SNPs are shown in Fig. 1 & S1. (Fig. 1A for rs3910384; Figure S1A, B & C for other tag SNPs; Table S9).