PTPRF and gastrointestinal stromal tumor: We collected two paired primary and metastatic tumors from two GIST patients, and observed several novel SNVs in the metastatic tumors but not in the primary tumors, including ARF1 (c.T443C, p. R148C), CAGE1 (c.G2425C, p.Q809H), PTGS1 (c.A35G, p.N12S), and PTPRF (c.G1768A, p.V590M) (Table 3).