Purpose: To develop a qPCR method to examine the 202 isoform of excision repair cross-complementation group 1 (ERCC1_202) and to evaluate its clinical utility as a predictive biomarker for platinum-based chemotherapy in non-small cell lung cancer (NSCLC).Methods: The relative complementary DNA (cDNA) quantification for ERCC1_202 was conducted using a fluorescence-based, real-time detection method and β-actin was used as a reference gene.Results: A strong correlation was observed between ERCC1_202 mRNA and ERCC1 mRNA levels in NSCLC cells (P < 0.001). 28 patients completed this research. Our results implied that as ERCC1_202 levels increased, the risk of progression (HR = 4.296, P = 0.011) and death (HR = 6.503, P = 0.001) increased. At multivariate analysis, high expression of ERCC1_202 was shown to be an independent predictive factor for time to progression (P = 0.047), and progression-free survival (P = 0.014). However, the high expression of ERCC1_202 was not an independent predictive factor for response (P = 0.324).Conclusions: This study suggests that the efficacy of platinum-based chemotherapy can be improved when customized according to the expression of ERCC1_202.

Background: This study was aimed to establish a novel method to simultaneously detect expression of four genes, ribonucleotide reductase subunit M1(RRM1), X-ray repair cross-complementing gene 1 (XRCC1), thymidylate synthase (TS) and class III β-tubulin (TUBB3), and to assess their application in the clinic for prediction of response of non-small cell lung cancer (NSCLC) to chemoradiotherapy. Materials and Methods: We have designed four gene molecular beacon (MB) probes for multiplex quantitative real-time polymerase chain reactions to examine RRM1, XRCC1, TUBB3 and TS mRNA expression in paraffin-embedded specimens from 50 patients with advanced or metastatic carcinomas. Twenty one NSCLC patients receiving cisplatinbased first-line treatment were analyzed. Results: These molecular beacon probes could specially bind to their target genes in homogeneous solutions. Patients with low RRM1 and XRCC1 mRNA levels were found to have apparently higher response rates to chemoradiotherapy compared with those with high levels of RRM1 and XRCC1 expression (p<0.05). The TS gene expression level was not significantly associated with chemotherapy response (p>0.05). Conclusions: A method of simultaneously detecting four molecular markers was successfully established and applied for evaluation of chemoradiotherapy response. It may be a useful tool in personalized cancer therapy.