In general, pHGGs have limited levels of lymphocyte infiltration compared to adult gliomas of the same tumour grade [142]; lymphocytes make up less than 3% of all CD45+ leukocytes in pHGGs, while adult HGGs may have lymphocytes that comprise up to half of their total CD45+ leukocyte population [63]. This evidence concerns the gene PTPRC and glioma.