The mutual migration and coexistence of four histological regions make it difficult to confirm the predominant component of PSP with limited pathological sampling.18 The ki-67 index is no more than 3% in normal cells and more than 10% in malignant tumors.9,19 However, the Ki-67 index was 3–10% in 7 cases (21.21%) of PSP in this study. Here, MKI67 is linked to cancer.