ERCC2 and adenocarcinoma: With the use of Cox multivariate logistic regression, we have demonstrated that factors which significantly shortened PFS in patients treated with cisplatin/gemcitabine based chemotherapy (overall fit of the model; χ2 = 46.59; p = 0.0025) were the following: poor PS (PS = 2, HR = 5.78, 95%CI: 2.18–15.34; p = 0.0005), higher stage of progression (IV, HR = 3.21, 95%CI: 1.41–7.28; p = 0.0055), diagnosis of non-adenocarcinoma type of NSCLC (HR = 3.14, 95%CI: 1.14–8.61; p = 0.0270) and CC genotype (2251A > C) of XPD/ERCC2 gene (HR = 12.62, 95%CI: 1.23–129.43; p = 0.0337).