In both brain and tumor samples, relative mRNA expression of key proline cycle enzymes, that is, POX/PRODH, PYCR1, PYCR2, and PYCR3, were evaluated, along with the expression of genes associated with ECM degradation, i.e., PEPD, MMP-2, and MMP-9. The gene discussed is PYCR1; the disease is neoplasm.