MPO and central nervous system cancer: To define molecular assays assessing the impact of COL22A1, IGFBP2, and MPO dysregulation in glioma behavior, RT-qPCR was first used to determine the expression of the corresponding mRNAs in normal human astrocytes (NHAs) and three grade 4 diffuse glioma cell lines (U87, LN229, and LN18).