Abstract: To explore the relationship between excision repair crosscomplementation group 1 (ERCC1) protein expression and clinical outcome of cis-platinum based adjuvant chemotherapy in non small cell lung cancer (NSCLC), in order to understand the possible mechanism of cisplatinum resistance in NSCLC and provide predictive bio-markers to tailor adjuvant chemotherapy regimens and improve survival and response in NSCLC patients. Methods We examined the ERCC1 expression in 112 NSCLC patients by immunohistochemical staining of paraffin embedded tumor tissues, analyzed the relationship between the ERCC1 expression and NSCLC patients′ age, pathology category, TNM stage, chemotherapy and survival, especially focusing on the relationship between the ERCC1 expression and adjuvant cis-platinum based chemotherapy and survival of NSCLC patients. ResultsIn NSCLC patients with positive ERCC1 protein expression, the survival of those who received adjuvant cis-platinum chemotherapy was significantly shorter than that of those did not receive adjuvant cis-platinum chemotherapy (P＜0.01); in NSCLC patients with negative ERCC1 expression, there were no significant differences between the survival of those with and without adjuvant cisplatin chemotherapy (P＞0.05), but there were trends that the former was longer than the latter. After excluding ERCC1 expression, survival was not related to patient age (χ²=1.008, P=0.297), but related to TNM stages; the earlier the TNM stages, the longer the survival (χ²=51.326, P=0.000); also it was related to pathological categories: the survival of adenocarcinoma was longer than that of squamous cell carcinoma (χ²=6.339, P=0.012). In all subgroups (patient age, TNM stage, pathology category), the survival of ERCC1 positive patients was longer than that of ERCC1 negative patients. Conclusion1. Cis-platinum chemotherapy may benefit the NSCLC patient with negative expression of ERCC1. 2. Positive ERCC1 expression indicates cisplatinum resistance, so ERCC1 may be used as a predictive bio-marker to tailor adjuvant chemotherapy. 3. ERCC1 protein expression might be an important index for prognosis.

Key words: Carcinoma, nonsmall cell lung, Excision repair crosscomplementation group 1, Cisplatin, Chemotherapy, adjuvant