PPM1D and diffuse midline glioma: Furthermore, Wang et al. found out that protein phosphatase 1D (PPM1D), which is a potential prognostic biomarker and correlates with immune cell infiltration in hepatocellular carcinoma [33], was an effective prognostic marker for elderly patients [31] and its silencing was associated with tumor sensitivity to treatment in gliomas [34], while Khadka et al. examined that PPM1D is a good prognostic marker for diffuse midline gliomas [35].