In most murine plasmacytomas, t(15:12) translocations, analogous to the T(8:14) translocations in Burkitt's lymphoma, fuse the 5' end of the c-Myc gene to an immunoglobulin heavy-chain gene; there are also the t(6:15) translocations, where the chromosome 6 breakpoint is near the constant region of kappa and the chromosome 15 sequences are from the Pvt1 locus [1,6]. The gene discussed is PVT1; the disease is plasmacytoma.