Some studies have compared histological grade and tumor biological markers—expressionof estrogen and progesterone hormone receptors; expression of human epidermal growthfactor receptor 2 (HER2); and the Ki-67 cell proliferation index—with ADC values,attempting to identify associations, although the results have been inconsistent andoccasionally contradictory(23).Belli et al.(24) studied 289patients with malignant carcinoma. The gene discussed is MKI67; the disease is neoplasm.