Excision repair cross-complementing group 1 (ERCC1) genotype for the single nucleotide polymorphism (SNP) cytosine-to-thymine substitution at codon 118 (C118T) interacts with post-radiotherapy plasma Epstein-Barr virus (EBV) DNA (pEBV) to identify favorable prognosis for a subgroup of patients with nasopharyngeal carcinoma (NPC), according to a study published in Cancer.
Edwin P. Hui, M.D., from The Chinese University of Hong Kong, and colleagues examined whether the ERCC1 genotype for the SNPs C118T and cytosine-to-adenine substitution at codon 8092 (C8092A) is prognostic in patients with NPC.
The authors evaluated the hypothesis using biomarker screening samples from a prospective, multicenter trial that used post-radiotherapy pEBV levels to screen high-risk NPC patients for adjuvant chemotherapy. ERCC1 SNPs were analyzed in 576 patients who underwent pEBV screening.
The researchers found that neither ERCC1 C118T nor C8092A genotype correlated with relapse-free survival (RFS) or overall survival (OS). In multivariate analyses, only post-radiotherapy pEBV status independently predicted RFS and OS.
A significant interaction was seen for ERCC1 C118T genotype and pEBV status (RFS, P = 0.0106; OS, P = 0.0067). In the pEBV-negative, but not pEBV-positive, population, ERCC1 C118T genotype correlated with both RFS and OS (hazard ratios, 1.67 and 2.31, respectively).
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“The ERCC1 C118T genotype may help to identify a favorable subgroup (approximately 7 percent) of pEBV-negative patients with NPC who have an excellent prognosis and can be spared the toxicities of further therapy,” the authors write.
One author disclosed financial ties to the pharmaceutical industry.