PIPOX and Familial prostate cancer: Our earlier studies revealed that the metabolite sarcosine and its biosynthetic enzyme, glycine N-methyltransferase (GNMT) were elevated in prostate cancer, while sarcosine dehydrogenase (SARDH) and pipecolic acid oxidase (PIPOX) that metabolize sarcosine, were reduced in prostate tumors [13, 14].