Close relation between 14q32/IGH translocations and chromosome 13 abnormalities in multiple myeloma: a high incidence of 11q13/CCND1 and 16q23/MAF.

Many B-cell tumors have chromosomal translocations that result from failures of the immunoglobulin (Ig) gene during V(D)J recombination, somatic hypermutation (SHM), and class switch recombination (CSR). Nearly half of all multiple myeloma (MM) patients have 14q32/IGH translocations in CSR, including the five common translocations of 11q13/CCND1, 6p21/CCND3, 4p16/FGFR3, 16q23/MAF, and 20q11/MAFB. Although 14q32/IGH translocations are closely related to the biological features of MM, the most consistent and powerful prognostic factor has been reported to be the loss of all (monosomy 13/-13) or part of chromosome 13 (del(13)(q14)/13q-). Our fluorescence in situ hybridization (FISH) analysis method was designed to detect -13/13q- and 14q32/IGH rearrangements in 23 MM patients. FISH disclosed 14q32/IGH translocations in 10 of the 23 (43.5%) patients. The common translocation partners of 14q32/IGH were 11q13/CCND1 (five patients) and 16q23/MAF (four patients), followed in third place by 4p16/FGFR3 (one patient). Nine of the ten patients carrying 14q32/IGH translocations had -13/13q-. Abnormalities of chromosome 13 included -13 in seven (70%) and del(13)(q14) in two (20%). Our results suggest a significant correlation between the presence of 14q32/IGH translocations and chromosome 13 abnormalities (P = 0.0276) in MM patients.