DNA Methylation of LRRC3B: A Biomarker for Survival of Early-Stage Non-Small Cell Lung Cancer Patients.

BACKGROUND: Previous studies support a tumor-suppressor role for LRRC3B across various types of cancers. We aimed to investigate the association between DNA methylation of LRRC3B and overall survival (OS) for patients with early-stage non-small cell lung cancer (NSCLC).
METHODS: This study included 1,230 patients with early-stage NSCLC. DNA was extracted from lung tumor tissues and DNA methylation was measured using Illumina Infinium HumanMethylation450 BeadChips. The association between DNA methylation and OS was first tested using Cox regression on a discovery cohort and then validated in an independent cohort. Next, the association between DNA methylation and gene expression was investigated in two independent cohorts. Finally, the association between gene expression and OS was investigated in three independent groups of patients.
RESULTS: Three novel DNA methylation sites in LRRC3B were significantly associated with OS in two groups of patients. Patients with hypermethylation in the DNA methylation sites had significantly longer survival than the others in both the discovery cohort (HR, 0.62; P = 2.02 × 10-05) and validation cohort (HR, 0.55; P = 4.44 × 10-04). The three DNA methylation sites were significantly associated with LRRC3B expression, which was also associated with OS.
CONCLUSIONS: Using clinical data from a large population, we illustrated the association between DNA methylation of LRRC3B and OS of early-stage NSCLC. IMPACT: We provide evidence of plausibility for building biomarkers on DNA methylation of LRRC3B for OS of early-stage NSCLC, thus filling a gap between previous in vitro studies and clinical applications. ©2018 American Association for Cancer Research.