immunoglobulin loci in multiple myeloma Cyclin D3 at 6p21 is dysregulated by recurrent chromosomal translocations to

Summary of 6p21 translocations with an immunoglobulinlocus in MM tumors Table 1 includes results obtained for the KMM-1 cell line and 9primary tumors. Eight tumors have a t(6;14)(p21;q32) transloca-tion, with cyclin D3 closely juxtaposed to a CH probe that contains39 IgH enhancer sequences in 7 of the tumors. In all informativecases, there is overexpression of cyclin D3. The cell line and 2tumors have no der(6), whereas the other 6 tumors have one copyof der(6). In contrast, 5 tumors have one copy of der(14), whereas 2tumors have 2 copies of der(14) and the remaining 2 tumors have 5or 6 copies of der(14). It is also notable that the KMM-1 cell lineand 5 of 6 informative tumors have a t(6;14) translocationbreakpoint that occurs within the sequences present in the CD3BAC clone, so that most breakpoints appear to be clustered in aregion that is fewer than 200 kb centromeric to cyclin D3. Thesingle tumor with a t(6;22)(p21;q11) translocation has no der(22),but cyclin D3 is closely juxtaposed to a Cl probe that contains 39Cl enhancer sequences.