PROS1 and central nervous system cancer: The POMGNT1 gene, encoding protein O-linked-mannose β-1,2-N-acetylglucosaminyltransferase 1, which is the next enzyme in acting after POMT1 and 2 by branching the α-DG O-glycosylation pathway in competence with the POMGNT2 gene product enzyme [131] (Fig. 2), has been found overexpressed in grade III and IV gliomas, this correlating with significantly lower survival in patients with glioblastoma (grade IV glioma) [114].