[Multi-omics approaches for revealing the etiology of cancer: from genomics, exposomics, metabolomics to system epidemiology].

Identifying risk factors of the disease are one of the main tasks of epidemiology. With the advancement of omics technologies (e.g., genome, transcriptome, proteome, metabolome, and exposome), cancer etiology research has entered the stage of systems epidemiology. Genomic research identifies cancer susceptibility loci and uncovers their biological mechanisms. Exposomic research investigates the impact of environmental factors on biological processes and disease risks. The metabolome is downstream of biological regulatory networks, reflecting the effects of the gene, environment, and their interactions, which can help elucidate the biological mechanisms of genetic and environmental risk factors and identify new biomarkers. Here, we reviewed the applications of genomic, exposomic, and metabolomic studies in the etiologic research on cancer. We summarized the importance of multi-omics approaches and systems epidemiology in cancer etiology research and outlined future perspectives.