93P DNA damage repair protein expression and EGFR gene status in NSCLC

Abstract

Background: Epidermal growth factor receptor (EGFR) is considered to be one of the key driver genes in non-small cell lung cancer (NSCLC). This study explored the potential association between EGFR and DNA damage repair gene expression (Ku70 and Rad51), and their relationship with prognosis in patients with NSCLC. Methods: We reviewed the clinical information of 79 patients. The expression of Ku70 and Rad51 were determined via immunohistochemistry in surgically resected of lung adenocarcinoma and densitometry analysis using image-pro plus 6.0 software. The clinical prognostic value of protein expression was investigated with univariate and multivariate survival analysis. Results: Compared with EGFR mutant patients, mean integral optical density (IOD) of Rad51 and Ku70 had no statistically significant difference in the wild type. Separating patients into low and high expression group according to the median value of IOD, Spearman's test showed no significant correlation between Ku70 and Rad51 expression level and EGFR gene status, while tumor tissue with T1-T2 staging had a lower Ku70 protein expression than T3-T4 (p < 0.05) according to the IOD. No statistical significant difference was found between in mean IOD of Ku70 and Rad51 between recurrence and non-recurrence. Kaplan-Meier analysis revealed that patients with Ku70 low expression tended to have poorer DFS than high expression group (20.6 vs. 22.7 months, p > 0.05). PFS of both Ku70 and Rad51 low expression group had an improving tendency comparing to high expression group (Ku70: 9.0 vs. 6.0 months, and Rad51: 10.0 vs. 7.0 months, both p > 0.05). Multivariate analysis showed, (negative vs. positive) was an independent impact factor of DFS; gender (female vs. male), EGFR status (mutant vs. wild type) and Ku70 expression level (low vs. high) were independent impact factors of PFS. Tabled 1Logistic regression between different proteins and possible impact factorProteinVariablesSEExp(B)pKu70EGFR0.4880.6840.688T-stage0.8330.0440.044Rad51EGFR0.4780.9250.925T-stage0.7320.1640.164 Open table in a new tab Conclusions: We provide clinical evidence that Ku70 protein expression level is lower in higher T-stage tumor tissue than the lower. DNA damage repair protein expression level has not been detected to have significant correlation with EGFR gene status and disease recurrence, while tumor high expression level of Ku70 protein might have worse response to systemic therapy. However, further study is required. Legal entity responsible for the study: Thoracic Oncology Center, West China Hospital Funding: State Key Laboratory of Biotherapy and Cancer Center of Sichuan province in China Disclosure: All authors have declared no conflicts of interest.