PPEF1 and malignant adrenal gland pheochromocytoma: Regarding prediction of NF1 inactivated tumors, we observed several genes that have been linked to cancer such as QPRT, which is highly expressed in malignant pheochromocytomas as compared to benign; RSL1D1 (CSIG), which stabilizes c-myc in hepatocellular carcinoma; PPEF, which is highly expressed in astrocytic gliomas as compared to normal brain tissue [50–52]; and PEG10, a poor prognostic marker and regulator of proliferation, migration, and invasion in several tumor types [53–55].