RESUMO
PURPOSE: Thyroid cancer is the most common malignancy affecting the endocrine glands. The incidence of his malady has conspicuously increased during the recent years. Thyroid diseases affect women approximately 3 times more often than men, and this incidence decreases after menopause. This gender difference has suggested that the female sex steroids stimulate the growth of the thyroid, the same as for the breast. In the present study, we investigated the expressions of estrogen receptor (ER) and progesterone receptor (PR) in thyroid lesions. METHODS: The tissues from 193 human thyroid glands (136 thyroid cancers and 57 adenomatous hyperplasias) were used for the present immunohistochemical assessment of the ER and PR expressions. RESULTS: The incidences of the estrogen and progesterone receptor positive cases were 19.7 and 41.5%, respectively. The incidence of the progesterone receptor positive cases was higher for females (46.5%) than for males (19.4%) however, the expression of estrogen receptor was not different significantly between the females and males. Higher expressions of estrogen and progesterone receptors were detected in the thyroid cancers than in the adenomatous hyperplasias. The PR expression seemed to correlate with the tumor size: a higher PR expression was found in the T3 cancers than in the T2 cancers. CONCLUSION: Our findings provide new insight that the ER and PR expressions may be related to the pathogenesis and progression of thyroid cancer.