Immunohistochemical study of oestrogen receptors in 351 human thyroid glands.

INTRODUCTION It is well recognised that the pathogenesis of thyroid diseases is complex and different factors such as genetic factors, iodine deficiency, sex, age, radiation therapy in childhood, growth stimulating antibodies, and other epithelial growth factors can influence them. Epidemiological features of thyroid tumours and experimental evidence suggest that female sex hormones may exert effects on the thyroid gland and its neoplasms. This possibility was addressed by investigating the expression of oestrogen receptor protein in 351 thyroid lesions. METHODS The tissues from 351 human thyroid glands comprising 130 nodular goitres and 221 neoplastic lesions were used for the present immunohistochemical assessment of oestrogen receptor expression. RESULTS Incidence of oestrogen receptor positive cases were 24 percent (31/130) for nodular goitres, 22 percent (8/37) for follicular adenomas, 11 percent (2/18) for follicular carcinomas, 31 percent (37/119) for papillary carcinomas, zero percent (0/35) for medullary carcinomas and zero percent (0/12) for undifferentiated carcinomas. The incidence of oestrogen receptor positivity, which is compatible with other studies, is higher in well-differentiated thyroid lesions. The incidence of oestrogen receptor reactivity does not significantly differ between females and males of different age groups and it does not correlate with lymph node status, and vascular and capsular invasions. CONCLUSION The relatively high proportion of oestrogen receptor positivity in goitres, follicular adenomas and papillary carcinomas, compared with its reactivity in other thyroid neoplasms, and contrasted against normal thyroid tissue, suggests that the incidence of oestrogen receptor reactivity tends to increase with better differentiation of thyroid lesions. This finding may have clinical relevance.