FGL2 and gastrointestinal stromal tumor: The interaction term between GIST FGL2 expression and the duration of adjuvant imatinib treatment was not statistically significant, but the analysis to detect the interaction was likely underpowered, since the numbers of patients with FGL2‐negative GIST were relatively small and the SSGXVIII trial was powered for testing of the two durations of adjuvant imatinib in a larger population of 400 GIST patients.