PGR and medullary thyroid gland carcinoma: On the basis of literature review, mucinous or colloid carcinomas metastasize later and are less likely to involve the lymph nodes at the emergence of the tumor.17 Although 30% to 40% of medullary carcinomas were PR positive in the cited study,18 the present study found only 11.5% of medullary carcinomas to express PR, suggesting that the medullary cancer patients examined in the present study are less likely to benefit from hormone suppression therapy.