May play a role in the regulation of cellular reactive oxygen species metabolism. May participate in cell growth regulation. Interacts with UNG. A V5 epitope-tagged construct has been shown to localize to the nucleus (PubMed:18676834). 5-7% of total FAM72A is associated with mitochondria around the nucleus in HEK293 cells (PubMed:21317926). May be up-regulated in malignant colon cancers, compared to normal colon and colon adenomas. Expression is also elevated in other common cancer types, including breast, lung, uterus, and ovary. Up-regulated in peripheral blood mononuclear cells following Epstein-Barr virus (EBV) infection or following transfection with EBV LMP1 protein. Highly homologous to GCUD2 but localized to a distinct locus. Belongs to the FAM72 family.