Previous studies indicated that CD5+ DLBCL and CD5+ CLL had higher frequencies of germline vs. somatically hypermutated IGHV genes compared with CD5− DLBCL [50], suggesting the COO of CD5+ DLBCL might be distinct from that of CD5− DLBCL and yet similar to that of CD5+ CLL [51]. This evidence concerns the gene CD5 and B-cell chronic lymphocytic leukemia.