With rare exceptions, MCL is characterized by a chromosomal translocation at t(11;14)(q13;q32) that relocates the CCND1 gene from its position at 11q13 to 14q32, placing it adjacent to the highly transcribed immunoglobulin heavy chain gene (IGH), resulting in overexpression of Cyclin D1, the downstream protein product of CCND1, and a potent driver of cell proliferation [2]. The gene discussed is CCND1; the disease is mantle cell lymphoma.