PTGS2 and central nervous system cancer: The magnitudes of fold change of the HLA-A (p = 0.08) and MIF (p = 0.10) genes were observed to be relatively higher in the tumour samples of high-grade glioma patients compared to low-grade glioma patients although this observation did not attain to a level of statistical significance, see Fig. 3a. Moreover, the following genes: CCL4, CSF2, PTGS2, and STAT3 were observed to be significantly under-expressed in the tumour samples of high-grade glioma patients (p < 0.001, versus low-grade glioma tumour samples), see Fig. 3b.