The PML gene provides instructions for a protein that acts as a tumor suppressor, which means it prevents cells from growing and dividing too rapidly or in an uncontrolled way. The PML protein is found in distinct structures in the nucleus of a cell called PML nuclear bodies (PML-NBs). In the PML-NBs, the PML protein interacts with other proteins that are involved in cell growth and division (proliferation) and self-destruction (apoptosis). The PML protein is able to block cell proliferation and induce apoptosis in combination with other proteins. Researchers believe that the structure of the PML-NBs is required for blocking proliferation and inducing apoptosis.