CCND1 and plasma cell myeloma: However, the presence of the loops in addition to the high number of retroviral integrations highlights the notion that this non-coding region of DNA plays a critical role in the regulation of CCND1. Moreover, to further emphasize its regulatory importance in the human genome, this upstream region is a site of recurrent chromosomal translocation breakpoints, particularly those specific to multiple myelomas [14, 15, 17].