PID/MTA2, also termed MTA1-L1, is a novel molecule that has been found to be involved in p53 pathway. PID/MTA2 modulates the enzymatic activity of the histone deacetylase complex and its expression reduces the levels of acetylated p53. Deacetylastion of p53 by PID/MTA2 represses p53-dependent transcriptional activation and modulates p53-mediated cell growth arrest and apoptosis. PID/MTA2 is ubiquitously expressed in human tissues.