Comparison of key immunophenotypic markers (CD5, CD10, CD23, CD25, CD103, cyclin D1) to differentiate chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), follicular lymphoma (FL), hairy cell leukemia (HCL), and splenic diffuse red pulp lymphoma (SDRPL). This evidence concerns the gene CD5 and hairy cell leukemia.