Two B-cell lines, designated as HF-1 and HF-4, were characterised. The cell lines have complicated karyotype abnormalities including a 14;18 translocation and an 8q24 breakpoint originating from t(2;8)(p11;q24) (HF-1) or t(1;8)(p21;q24) (HF-4). The lines have BCL2 rearrangement and they are positive for CD19, CD20, CD22, CD39. HF-1 is also positive for IgG, and HF-4 is positive for IgM and IgD. On Northern blot analyses, the 2.6-kb and 4.2-kb transcripts corresponding to the major transcripts of CMYC and BCL2, respectively, were seen. In Western blot as well as in FACS (fluorescence-activated cell sorting) analysis the presence of BCL2 protein in the both HF-1 and HF-4 cells was demonstrated. The cell lines are expected to serve as an important tool in the study of the chromosomal mechanism activating cellular oncogenes, the somatic hypermutation mechanism of antigen-activated B cells and the apoptosis of B cells.