Patients with GIST with KIT exon 11 homozygous mutations and KIT intron 10/exon 11 junction deletions had the highest recurrence rate, which was even worse than that in patients who had GIST with KIT exon 9 duplication or other exon 11 deletions involving codons 557‐558 and exon 11 deletion involving two or more codons (Figure 5A). This evidence concerns the gene KIT and gastrointestinal stromal tumor.