The IHC was largely performed for further characterization of the lymphoid cells, including a cyclin D1 stain to exclude mantle cell lymphoma or CD15/LeuM1 and CD30 to exclude HL (14 cases, 88% of the cases with IHC), for further characterization of an epithelial malignancy (one case, 6%) or for both indications (one case, 6%). The gene discussed is CCND1; the disease is mantle cell lymphoma.