These newly formed structures will be referred to as PML cages, since they resemble enlarged PML-NBs that have been observed in patients with immunodeficiency, centromeric instability and facial dysmorphy (ICF) syndrome or in varicella zoster virus-infected cells and have been shown to encase cellular or viral components (Reichelt et al., 2011; Luciani et al., 2006). This evidence concerns the gene PML and ICF syndrome.