bcl-2 is a marker for the translocation t(14;18)(q32;q21) indicative of follicular B-cell lymphoma. We studied 115 cases of lymphoproliferative disease with the polymerase chain reaction for bcl-2 oncogene using biotin and radiolabeled probes to the major breakpoint and minor cluster regions. Twenty-three percent of B-cell lymphomas were positive for bcl-2. These included 12 of 20 cases of nodular follicular center cell lymphoma (nine small cleaved cell, one mixed small and large cell, and two large cell types). bcl-2 translocation was detected in only three of 45 cases of diffuse B-cell lymphoma, and cases of AIDS-related malignant lymphoma, monocytoid B-cell lymphoma, and mantle zone lymphoma were all negative. Nonneoplastic lymphoid proliferations were negative for bcl-2 including nine cases of abnormal follicular hyperplasia from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex. Cases of T-cell lymphoma and five cases of Hodgkin's disease were also negative. The polymerase chain reaction for bcl-2 is a rapid, sensitive technique in the evaluation of follicular B-cell proliferations, and the use of biotinylated probes and the alkaline phosphatase reaction eliminates the requirement for radioactive reagents.