MKI67 and thyroid gland disorder: To evaluate the correlations between pathological features with prognostic value, we assessed the associations between age at diagnosis, gender, pre-operative serum calcitonin levels, tumor size, location, growth pattern, stromal amyloid, mitotic activity/2 mm2, Ki67 proliferation index, tumor necrosis pathologic T category, AJCC stage, coexisting thyroid pathology, and five elements considered to be essential for risk stratification, namely, PNI, LVI, mETE, multifocality, and LNM (Table S1).