Cytogenetic studies on IgA/lambda-producing murine plasmacytomas: regular occurrence of a T(12;15) translocation.

Seven IgA/lambda-producing murine plasmacytomas had the 12;15 translocation, previously found in IgA/kappa-producing plasmacytomas, and lacked the rcpT(6;15) translocation, also found in some kappa producers. The results suggest that the generation of the 12;15 translocation is an important, perhaps essential event during the genesis of plasmacytomas. The possibility that the distal region of chromosome 15 may contain a "supergene" area involved with the differentiation and/or normal responsiveness of various types of lymphoreticular cells, must be seriously considered on the basis of the present and previous evidence on plasmacytomas, as well as the extensive evidence now available on the role of chromosome 15-changes in the genesis of murine lymphomas. The involvement of chromosome 12 is of interest in view of the fact that it is known to carry the heavy-chain immunoglobulin determinants.