PML and cancer: In humans, PML deficiency occurs commonly in a broad spectrum of human cancers including lung, prostate and breast carcinoma, lymphomas, CNS tumors, and germ cell tumors, through a mechanism that involves aberrant ubiquitin-mediated degradation (Koken et al., 1995; Gurrieri et al., 2004a; Scaglioni et al., 2006).