Abstract 3776: Examination of ERCC1 status in circulating tumor cells as a prognostic tool for patients with nasopharyngeal carcinoma

• Published in: Cancer research (Chicago, Ill.) Vol. 77; no. 13_Supplement; p. 3776
• Main Authors: Hui, Edwin P., Ma, Brigette BY, Chan, KC Allen, Chan, Charles ML, Wong, SC Cesar, To, Ka Fai, Loong, Herbert HF, Mo, Frankie KF, Ngan, Roger KC, Chan, Anthony TC
• Format: Journal Article
• Language: English
• Published: 01-07-2017
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM2017-3776

Abstract
Investigation of the expression pattern of DNA-repair protein excision repair cross-complementation group 1 (ERCC1) has been reported to allow selection of patients with non-small cell lung cancer who are likely to benefit from cisplatin-based therapy. Recent evidence suggests that ERCC1 expression may also find prognostic use in patients with nasopharyngeal carcinoma (NPC). We evaluated ERCC1 expression and genotype from NPC tissues and peripheral blood mononuclear cells of patients with NPC. ERCC1 expression was detected in 61/77 cases (79.2%) with varying intensities, where high ERCC1 expression significantly associated with worse relapse-free survival (RFS) (HR 2.34, 1.06-5.16, p=0.036). In addition, the presence of ERCC1 C118T genotype was significantly associated with favorable RFS and overall survival (OS) in a subgroup of patients with undetectable post-treatment plasma EBV DNA. These findings support a prognostic role for ERCC1 examination in NPC. However, the invasive nature of obtaining biopsy samples for tumor marker studies is a major hindrance of this approach. To facilitate the investigation of ERCC1 expression in a noninvasive manner, we have developed a negative selection immunomagnetic method for isolating circulating tumor cells from patient blood. Cell line spike-in experiments reveal a mean recovery rate of 66% for NPC cells with greater than 99% removal of non-targeted blood cells. Specificity of CTC identification was confirmed by detection of the expression of the Epstein-Barr virus encoded small RNA (EBER) in the CTCs. This method also allowed the simultaneous analysis of the expression of multiple protein markers including CD45, cytokeratin and ERCC1. It is expected that the development of noninvasive methodologies for tumor marker studies will facilitate their clinical application for improved patient care and monitoring in the future.
Note: This abstract was not presented at the meeting.
Citation Format: Edwin P. Hui, Brigette BY Ma, KC Allen Chan, Charles ML Chan, SC Cesar Wong, Ka Fai To, Herbert HF Loong, Frankie KF Mo, Roger KC Ngan, Anthony TC Chan. Examination of ERCC1 status in circulating tumor cells as a prognostic tool for patients with nasopharyngeal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3776. doi:10.1158/1538-7445.AM2017-3776