Sequencing of the exomes — the coding region of the genome — of individuals with hepatocelullar carcinoma (HCC) is reported this week in Nature Genetics.

HCC is the third leading cause of cancer related deaths worldwide, and carries a high mortality rate. Infection with either hepatitis B or hepatitis C virus, as well as environmental factors including alcohol consumption, are known risk factors for HCC.

Kenneth Kinzler and colleagues sequenced the exomes of ten individuals with hepatitis C virus (HCV) associated HCC. They identified inactivating mutations in the ARID2 gene and establish this as an HCC tumor suppressor gene. They examine additional cases, and found that ARID2 is mutated in 18.2% of individuals in their sample with HCV associated HCC.