PRKDC and squamous cell carcinoma: In the analysis of squamous cell carcinoma, we chose three SNPs with longer survival time, rs344781 (PLAUR, TT homozygote), rs2273953 (TP73, CC homozygote) and rs12334811 (DNPK1, GG homozygote), to do stepwise regression analysis, and the results are shown in Fig. 1.