By contrast, homozygous deletions of the 9p21 locus, which FISH detection of CDKN2 loss most often reflects, is a documented association with progression and aggression in diffuse, large, B-cell lymphoma and mycosis fungoides28,30; furthermore, Tsang et al31 reported a unique case of primary cutaneous follicle center cell lymphoma, of high-grade cytological morphology, with CDKN2A deletion that progressed to diffuse, large, B-cell lymphoma. The gene discussed is CDKN2A; the disease is B-cell non-Hodgkin lymphoma.