The translocation breakpoints mapped in different cell lines and patients vary within the IGH locus on chromosome 14 and extend between 47 kb and 300 kb in the region upstream of CCND1. A known consequence of these translocations is overexpression of CCND1 (Fig. 4A) which becomes a driving factor in the development of the myeloma. This evidence concerns the gene CCND1 and plasma cell myeloma.