In primary human tumor samples (for instance in carcinomas from various organs such as skin, breast, colon, lung, or prostate), PML expression and NB formation are initially increased upon transformation but lost when the cancer cells turn invasive (Gambacorta et al., 1996; Gurrieri et al., 2004; Koken et al., 1995), likely mirroring senescence/apoptosis in the natural history of human cancer development. The gene discussed is PML; the disease is cancer.