TP53I11 is a 177 amino acid tumor suppressor belonging to the p53-induced protein gene (PIG) family. The PIG gene family encodes redox-controlling proteins that are involved in p53 tumor suppressor activity. It is suggested that PIG11 is involved in arsenic trioxide As(2)O(3)-induced apoptosis in certain cell lines and may play a significant role in tumor suppression through promotion of cell apoptosis. The gene encoding PIG11 maps to human chromosome 11, which houses over 1,400 genes and comprises nearly 4% of the human genome.