TP53 and gastrointestinal stromal tumor: For patient NCCS-GIST-07 with small bowel GIST progressing on 1st-line treatment with imatinib, ctDNA detected TP53 c.879_880del and SETD2 c.2238del mutations, but not the known KIT exon 11 c.1708_1728del mutation (Table 2).