A new era for understanding genetic evolution of multistep carcinogenesis.

Cancer development is a multistep process involving genetic and cellular alterations, and recent advances in next-generation sequencing have elucidated mutation landscapes of premalignant lesions as well as early- and late-stage tumors. In this issue of Journal of Gastroenterology, Kim and colleagues contributed to the better understanding of genetic events in putative precursors of hepatocellular carcinoma (HCC). Precancerous tissues are divided into canonical and non-canonical types, which share common driver mutations with cancerous lesions or not, and potential gatekeeper gene(s) for clonal selection play a critical role in driving precursors to cancers not only in HCC, but also in esophageal, gastric, colorectal, and pancreatic cancers.