Southern blot analysis was performed with a panel of DNA probes to detect rearrangements of c-myc,bcl-1,bcl-2 andbcl-1 in 14 cases of B-cell non-Hodgkin's lymphoma (NHL) with a clonal cytogenetic rearrangement involving the chromosome 14q32 locus and no known donor chromosome [t(14;?)(q32;?)]. In our experience, 21% of all chromosomal abnormalities involving the 14q32 locus in B-cell NHL are of this type. We found oncogene rearrangements in five of the 14 cases:bcl-1 rearrangement on one mantle zone lymphoma,bcl-2 rearrangements in two follicular lymphomas, and c-mycrearrangements in two small noncleaved cell lymphomas. We conclude that a 14q32 + abnormality of unknown origin is a relatively frequent karyotypic finding in B-cell NHL. In one third of the cases, known oncogenes that have been previously described in reciprocal translocations involving the immunoglobulin heavy chain locus were shown to be involved in the 14q32 + abnormality. The translocations in the other cases are likely to have involved one of the above oncogenes with breakpoints not revealed by the probes employed, other known oncogenes, or oncogenes that have not yet been identified.