The CDC73 gene (formerly known as HRPT2) provides instructions for making a protein called parafibromin. This protein is found primarily in the nucleus of cells and is likely involved in regulating gene transcription, which is the first step in protein production. Parafibromin functions as a tumor suppressor, which means it keeps cells from growing and dividing (proliferating) too rapidly or in an uncontrolled way. When parafibromin is found outside the nucleus, it appears to be involved in the organization of the cell's structural framework (the cytoskeleton).