Specificity of the deletion of chromosome No. 15 in mouse plasmacytoma: brief communication.

Q-banding studies in two independent hyperdiploid mouse plasmacytomas, 63-1 and the NP-38-ABCD subline of MSPC-1, revealed that deletion of a No. 15 chromosome was common. The deletion of No. 15 appeared to result from a translocation between No. 12 and 15 in the NP-38-ABCD, as in most plasmacytomas. In 63-1, however, No. 10 was probably a recipient chromosome of the missing segment from the deleted No. 15, and both chromosomes No. 12 remained intact. These karyotypic features suggest that the deleted No. 15 is a tumor-specific marker chromosome in mouse plasmacytoma and that an abnormality of No. 12 is not essential for development of the tumor. The constitution of chromosomes in the two plasmacytomas remained remarkably stable in their homogeneous modal population.