Novel genetic variants of SYK and ITGA1 related lymphangiogenesis signaling pathway predict non-small cell lung cancer survival.

Abstract

Although lymphangiogenesis is a vital step in lung cancer metastasis, the association between lymphangiogenesis and non-small cell lung cancer (NSCLC) survival remains unclear. Since single-nucleotide polymorphisms (SNPs) have been reported to predict NSCLC survival, we investigated associations between SNPs in lymphangiogenesis-related pathway genes and NSCLC survival in a discovery genotyping dataset of 1,185 patients from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and validated the findings in another genotyping dataset of 984 patients from the Harvard Lung Cancer Susceptibility Study. We evaluated associations between 34,509 genetic variants (3252 genotyped and 31,257 imputed) in 247 genes involved in lymphangiogenesis-related pathway and NSCLC survival. After validation, we finally identified two independent SNPs (SYK rs11787670 A>G and ITGA1 rs67715745 T>C) to be significantly associated with NSCLC overall survival (OS), with adjusted hazards ratios of 0.77 and 0.83 (95% confidence interval =0.66-0.90, P=7.20×10-4) and 0.84 (95% confidence interval =0.75-0.92, P=3.50×10-4), respectively. Moreover, an increasing number of combined protective alleles of these two SNPs was significantly associated with an improved NSCLC OS and disease-specific survival (DSS) in the PLCO dataset (P trend=0.011 and 0.006, respectively). Furthermore, the addition of these protective alleles to the prediction model for the 5-year survival increased the time-dependent area under the curve both from 87% to 87.67% for OS (P=0.029) and from 88.54% to 89.06% for DSS (P=0.022). Subsequent expression quantitative trait loci (eQTL) functional analysis revealed that the rs11787670 G allele was significantly associated with an elevated SYK mRNA expression in normal tissues. Additional analyses suggested a suppressor role for both SYK and ITGA1 in NSCLC survival. Collectively, these findings indicated that SYK rs11787670 A>G and ITGA1 rs67715745 T>C may be independent prognostic factors for NSCLC survival once further validated.