“…In contrast to CaSr signalling, cyclin D1 signalling is involved in cell cycle progression (41,55,100,131,132,(150)(151)(152)(153). aberrant activation of cyclin D1 signalling has been well described in a large subset of parathyroid tumors, implicating altered CCND1/PRAD1, CDKIs, and ZFX genes (2,11,28,41,55,100,131,132,(150)(151)(152)(153)(154)(155). CCND1/PRAD1 (11q13) is a proto-oncogene encoding the cyclin D1 protein, a holoenzyme thought to inactivate the tumor-suppressor retinoblastoma protein (rb) (41,55,100,131,132,(150)(151)(152)(153)156).…”