摘要Genome-wide association studies(GWAS)have identified thousands of genomic loci asso-ciated with complex diseases and traits,including cancer.The vast majority of common trait-associated variants identified via GWAS fall in non-coding regions of the genome,posing a chal-lenge in elucidating the causal variants,genes,and mechanisms involved.Expression quantitative trait locus(eQTL)and other molecular QTL studies have been valuable resources in identifying can-didate causal genes from GWAS loci through statistical colocalization methods.While QTL colo-calization is becoming a standard analysis in post-GWAS investigation,an easy web tool for users to perform formal colocalization analyses with either user-provided or public GWAS and eQTL datasets has been lacking.Here,we present ezQTL,a web-based bioinformatic application to interactively visualize and analyze genetic association data such as GWAS loci and molecular QTLs under different linkage disequilibrium(LD)patterns(1000 Genomes Project,UK Biobank,or user-provided data).This application allows users to perform data quality control for variants matched between different datasets,LD visualization,and two-trait colocalization analyses using two state-of-the-art methodologies(eCAVIAR and HyPrColoc),including batch processing.