MKI67 and neoplasm: Yamamoto et al[15] have defined 3 prognosis categories of EGISTs on the basis of a combination of the mitotic rate and Ki-67 proliferation index tumor: a high-risk group (≥5/50 HPF with ≥10% Ki-67), an intermediate-risk group (≥5/50 HPF with <10% Ki-67 or <5/50 HPF with ≥10%Ki-67), and a low-risk group (<5/50 HPF with <10% Ki-67).