The Sydney grading scheme is three-tiered and defined low-grade tumors as those having MI < 3 mitoses per 2 mm2, a Ki67 proliferative index of < 3%, and no tumor necrosis; intermediate grade as an MI of 3-20 mitoses per 2 mm2 or a Ki67 proliferative index of 3%-20% without necrosis, or a low proliferative index with necrosis; and high grade as intermediate proliferative activity with necrosis, or high proliferative activity with or without necrosis. This evidence concerns the gene MKI67 and neoplasm.