MTCP1 and B-cell chronic lymphocytic leukemia: Here, we identified an index CLL patient bearing an uncommon, reciprocal t(X;14)(q28;q32) translocation joining the MTCP1 locus with immunoglobulin heavy chain regulatory elements (IGH; 14q32), an event analogous to the IGH translocations with MYC, CCND1, or BCL2 genes driving various B-lymphomas39,40.