XPC mRNA level may predict relapse in never-smokers with non-small cell lung cancers

Background. Disease recurrence and distant metastasis are the major causes of death in resected non-small cell lung cancer (NSCLC). The prognostic marker for never-smokers with this disease remains to be identified. To improve patient outcome, establishing an adjacent molecular marker to predict relapse of NSCLC in never-smokers is needed. Methods. Three hundred two lung tumors from NSCLC patients and normal lung tissues from 68 noncancer subjects were enrolled to evaluate XPC (xeroderma pigmentosum group C) mRNA expression by quantitative real-time reverse transcriptase polymerase chain reaction. Receiver operating characteristic curve analysis was used to search for a feasible cutoff point of XPC mRNA levels for predicting recurrence-free survival. Of the 326 patients, 214 were confirmed as only receiving surgical resection. Kaplan-Meier and multivariate Cox regression analysis were used to assess the prognostic value of XPC mRNA level in lung tumors from patients who only received surgical resection. Results. Receiver operating characteristic curve analysis indicated 30.28 as a cutoff point, and thus 150 and 64 tumors with low- and high-XPC mRNA expression were categorized in this study population. Low-XPC mRNA appeared with more frequency in never-smokers and in late-stage (stage II-III) disease than smokers and early-stage disease (stage I). Kaplan-Meier analysis indicated that patients with low-XPC mRNA had shorter recurrence-free survival than that found in never-smokers (P = 0.002), but not in smokers (P = 0.296). Cox regression analysis further revealed that low-XPC mRNA may independently predict relapse in lung cancer of never-smokers (hazard ratio 2.34, 95% confidence interval 1.21-4.51, P = 0.011). Conclusions. Low-XPC mRNA may predict relapse in lung cancer patients who are never-smokers.