Several lines of evidence support the importance of cyclin D1 nuclear location in aberrant growth including elegant studies showing that a mutant of cyclin D1 (D1T286A), that is defective in phosphorylation-mediated nuclear export, induces cell transformation in cell culture assays and triggers B-cell lymphoma in a mouse model of mantle cell lymphoma69,70. This evidence concerns the gene CCND1 and B-cell non-Hodgkin lymphoma.