Two Epstein-Barr virus (EBV)-negative lymphoma B-cell lines, HBL-1 and HBL-2, were established from a pleural effusion and a lymph node biopsy of two patients with diffuse large cell lymphoma. HBL-1 and HBL-2 showed the characteristics of activated B-cells in B-cell lineage, as did original lymphoma cells. Chromosome analyses revealed that HBL-1 exhibiting 14q+ marker-positive lymphoid cancer showed a new subclass of 14q32 translocation resulting from a translocation between chromosomes 14 and 16, which had been masked in a complex translocation involving five chromosomes, and that HBL-2 had a 14q+ marker chromosome, the result of an 11;14 translocation [t(11;14)(q13;32)]. Successful heterotransplantation into athymic nude mice demonstrated tumorigenicity of HBL-1 and HBL-2. The transplantability and tumor growth rate of HBL-2 were higher and more rapid than those of HBL-1. HBL-1 and HBL-2 appear useful for facilitating therapeutic investigations as well as immunologic and oncogenic studies in B-cell lymphomas.