Specific chromosome translocation in pristane-induced plasmacytomas of NZB mice

The karyotypes of 3 pristane (2,6,10,14-tetramethyl-pentadecane)-induced NZB mouse plasmacytomas producing IgA (plasmacytoma TEPC-3660), IgG3K (plasmacytoma TEPC-6583), and IgG2aK plus IgG3K (plasmacytoma TEPC-6906) were studied in early transplantation generations by the combined Hoechst 33258-quinacrine mustard banding method. The two IgG producers (TEPC-6583 and TEPC-6906) showed diploid chromosome number, whereas the IgA producer (TEPC-3660) showed hypotetraploid chromosome number. Banding analysis revealed that these 3 plasmacytomas consistently had the t(12;15) translocation with the specific breakpoints at 12F2 and 15D2. Taken together with the previous observation of t(12;15) in plasmacytomas of BALB/c and C3H mice, these results suggest that the t(12;15) is specific for murine plasmacytomas and that the putative gene(s) on the t(12;15) may participate in the genesis of murine plasmacytomas.