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.