Prognostic value of ERCC1 and RRM1 in NSCLC patients with smoking history or not

Introduction: We aimed to assess the expression of ERCC1 and RRM1 in NSCLC patients with smoking history or not and investigate the therapeutic effect of biomarker-guided chemotherapy in those patients. Patients and methods: A total of 131 NSCLC patients at stage IIIb or IV were enrolled and divided into two groups based on their smoking history. Group A were smokers (n=67); Group B were non-smokers (n=64). The expression of ERCC1 and RRM1 were determined by real-time polymerase chain reaction analysis (RT-PCR). Clinicopathological characteristics, tumor response and patient survival were monitored for both groups. Results: In our study, the expression of ERCC1 was significantly higher in smoking patients as compared with non-smoking group (P=0.028). Patients' characteristics in both groups were compared and there were no significant difference in patients age, tumor size or pathological types, but more male patients were occurred in Group A (P=0.001). Notably, the patients with low mRNA expression of ERCC1 (X-2=6.194, P=0.013) and RRM1 (X-2=5.012, P=0.025) were more sensitive to chemotherapy than patients with high expression levels. Compared with Group A, the patients in Group B displayed a higher response rate (59.3% vs. 32.8%; P=0.045), a lower 1-year recurrent rate (25.0% vs. 52.2%; P=0.001), a longer median progression-free survival (PFS) time (12.0 months vs. 14.1 months, P=0.008) and median overall survival (OS) time (22.9 months vs. 27.6 months; P=0.005). Conclusion: In summary, the expression levels of ERCC1 and RRM1 are mediated by smoking and correlated with the sensitivity to chemotherapy together with the clinical outcome of NSCLC patients. Our study suggests the adverse effect of smoking on the prognosis of NSCLC patients.