Allele-Specific MicroRNA-Binding Variants at Colorectal Cancer Risk Loci in a Hispanic/Latino Population: An Integrative GWAS, All of Us, and Epigenomic Analysis

Colorectal cancer (CRC) disproportionately affects Hispanic individuals, who remain underrepresented in genomic discovery and lack ancestry-matched functional resources. Many CRC risk variants are non-coding, and those in 3' untranslated regions (3' UTRs) can alter microRNA (miRNA) binding sites and reprogram post-transcriptional gene regulation. Here, we identify allele-specific miRNA-binding variants at CRC risk loci within the Hispanic population using a discovery pipeline anchored to Hispanic-relevant resources. CRC-associated 3' UTR variants were compiled from the GWAS Catalog, further verified in Hispanic/Latino individuals using the All of Us Research Program cohort (n = 453), expanded into proxy sets using Admixed American-specific linkage disequilibrium, annotated against Ensembl transcripts, and evaluated with TargetScan and RNAhybrid.

Screening of 38 CRC-associated 3' UTR SNPs identified 19 variants that alter miRNA binding across nine genes, with each gene represented by a variant confirmed in the Hispanic cohort. Three oncogenic loci, DCBLD2 (lead SNP rs11552978), GREM1 (lead SNP rs10318), and SMC1B (rs3747239, prioritized as an AMR-specific proxy in near-complete LD with confirmed lead rs6007600), met all prioritization criteria. In each case, the risk allele disrupts a strong miRNA-binding site, while the gene shows increased tumor expression, weak correlation between expression and methylation, and an absence of local active transcriptional chromatin marks (cCREs/H3K27Ac).

These results suggest that the variants promote gene overexpression through loss of miRNA-mediated repression rather than changes in promoter methylation. Overall, the study identifies non-coding CRC susceptibility variants in the Hispanic population and highlights DCBLD2, GREM1, and SMC1B as strong candidates for functional validation.