CD274 and medullary thyroid gland carcinoma: Analyzing data from 176 patients with advanced TC, our study found significant variability in PD-L1 expression with Oncocytic Thyroid Cancer (OTC) and Anaplastic Thyroid Cancer (ATC) exhibiting the highest frequencies of PD-L1 expression, while Medullary TC (MTC) and Papillary TC Follicular Variant (PTCFV) did not show any PD-L1 expression.