Proline-rich acidic protein 1, also known as Uterine-specific proline-rich acidic protein, UPA and PRAP1, is a secreted protein. PRAP1 is abundantly expressed in the epithelial cells of the liver, kidney, gastrointestinal tract and cervix. PRAP1 is up-regulated by butyrate, trichostatin A and 5'-aza-2' deoxycytidine. PRAP1 may play an important role in maintaining normal growth homeostasis in epithelial cells. PRAP1 is suppressed through epigenetic mechanisms involving histone deacetylation and methylation. PRAP1 has been shown to cause cell growth inhibition in cancer cell lines.