We have two principal aims in this multi-institutional study of FISH performance in diffuse large B-cell lymphoma and high-grade B-cell lymphoma: 1) compare the success rate of MYC, BCL2, and BCL6 FISH hybridization across FNAB with cell block, core biopsy, and excisional biopsy, 2) compare FNAB to either core biopsy or excisional biopsy for FISH from the same patient. The gene discussed is BCL6; the disease is diffuse large B-cell lymphoma.