Expression of Estrogen Receptor, Progesterone Receptor, and Vascular Endothelial Growth Factor-A in Thyroid Cancer

Abstract

Thyroid cancer is three times more prevalent in females but the role of sex hormones in its pathogenesis is unknown. Vascular endothelial growth factor (VEGF) is crucial for angiogenesis. Its expression correlates with tumor aggressiveness and metastatic potential. We determined the expression of estrogen receptor (ER), progesterone receptor (PR), and VEGF-A in thyroid neoplasms to see if expression correlated with age and sex, histological type, cancer stage, and clinical outcome. Pathological samples of thyroid cancer diagnosed from 2002 to 2007 were stained immunohistochemically for ER, PR, and VEGF-A. Grading was done qualitatively in intensity and quantitatively in percentage. Both grades were multiplied to assign a final score. One hundred and four patients were studied, of which 82 per cent were female with a mean age of 53 years (range 23-86 years). Most tumors were papillary in origin. Overall, final scores were significantly higher for ER (1.41) and PR (1.0) in tumors compared with the ER (1.07) and PR (0.42) in normal tissue ( P = 0.005 and < 0.001, respectively). Conversely, VEGF-A had lower expression in tumor tissues (7.2) than in normal tissue (8.2) ( P = 0.024). No predilection was found for specific age group, gender, histological subtype, or stage of the cancer. Thus, compared with normal tissue, ER and PR expression is higher and VEGF-A expression is lower in tumor thyroid tissue. The over-expression of sex hormone receptors in thyroid tumor suggests their role in thyroid cancer pathogenesis and needs further investigation.