FOLH1 belongs to the type II transmembrane glycoprotein of the M28 peptidase family. This protein acts as glutamate carboxypeptidase on various alternative substrates, including folate and neuropeptide N-acetyl-1-aspartate-1-glutamate, and is expressed in many tissues such as the prostate, central and peripheral nervous systems, and kidneys. The mutation of this gene may be related to impaired intestinal absorption of dietary folate, leading to low blood folate levels and subsequently causing hyperhomocysteinemia. The expression of this protein in the brain may be associated with many pathological conditions related to glutamate excitotoxicity. In the prostate, this protein is upregulated in cancer cells and is used as an effective diagnostic and prognostic indicator for prostate cancer.