In GIST, the mutation probabilities of each c-Kit site are Exon11 (52%~58%), Exon18 (13% ~14%), Exon9 (6% ~ 9%), Exon12 (0.6% ~ 2%), Exon13 (1% ~ 3%), Exon14 (1% ~ 3%), and Exon17 (0% ~ 1%) (9). The gene discussed is KIT; the disease is gastrointestinal stromal tumor.