In terms of prognosis, the 2022 World Health Organization (WHO) classification of endocrine and neuroendocrine tumors recommends that MTCs be graded based on the mitotic index, the presence of tumor necrosis, and the Ki-67 proliferation index, in which high-grade lesions display necrosis, a mitotic count ≥ 5 per 2 mm2, and/or a Ki-67 index of ≥ 5% [5, 19]. Here, MKI67 is linked to neoplasm.