Patient and disease characteristics by age group at diagnosis. Patients diagnosed below the age of 18 had characteristics associated with pediatric-type GIST: female gender (panel A), predominantly stomach primaries (panel B), prolonged overall survival (panel C), and wild-type GISTor SDH mutations (panel D). Patients diagnosed over age 35 had characteristics associated with adult-type GIST: slight male preference (panel A), slight preference for stomach primary tumor location followed closely by small intestine primaries (panel B), shorter overall survival (panel C), and dominated by KIT mutations (panel D). The 18-35 at diagnosis age group had characteristics between those of pediatric-type and adult GIST. Tumor locations were provided as free text and are depicted as a relative percentage within each age-group (panel B). Some sites have been grouped post hoc including, multiple GI (stomach and esophagus, stomach and small intestine, small and large intestine), and "other" which includes all remaining reported primary tumor sites (table 2); the rest were as reported (esophagus, stomach, small intestine, colon or rectum/anus). This was an attempt to adhere to published groupings without changing the data as reported. Multi GI, colon, and rectum/anus in the > 35 group, and multi GI in the 18-35 group were ~3% (2.9-3.3%); the remaining unlabelled sites were all < 2% of age-group (0.8-1.6%).