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). The gene discussed is CD5; the disease is follicular lymphoma.