Lung tissues
Lung tissues were collected from patients who underwent lung resection surgery at the three participating sites; Laval University, University of British Columbia, and University of Groningen.
Genotyping
DNA samples were genotyped using the Illumina Human1M-Duo BeadChip array.
Imputation
Genotypes were imputed in each cohort with the Michigan Imputation Server (PMID: 27571263) using the Haplotype Reference Consortium version 1 (HRC.r1-1) data as reference set (PMID: 27548312).
Gene expression
Gene expression profiles were obtained using a custom Affymetrix array (see GEO platform GPL10379). Gene expression values were adjusted for age, sex and smoking status.
Cis-eQTL
eQTLs were calculated by using linear regression model and additive genotype effects as implemented in QTLtools (PMID: 28516912). Cis-eQTLs were defined by a 2 Mb window, i.e., 1 Mb distance on either side of the SNP. The results were then combined in a fixed-effects meta-analysis with inverse-variance weighting as implemented in METAL (PMID: 20616382).