Saratsis et al. [112] used mass spectrometry to assess the proteome of 15 CSF specimens collected from patients with DIPG showing selective upregulation of Cyclophilin A (CypA) and dimethylarginase 1 (DDAH1) in DIPG compared with controls, suggesting that detection of these factors in CSF and serum has potential clinical application, with implications for assessing treatment response and detecting tumor recurrence in patients with DIPG. Here, DDAH1 is linked to diffuse intrinsic pontine glioma.