The β form of the estrogen receptor is predominantly expressed in the Papillary cystic neoplasm of the pancreas

Papillary cystic neoplasm (PCN) of the pancreas is a low-malignancy tumor affecting predominantly young females. Sex steroid hormones have been involved in its development and/or growth. Estrogen receptor (ER) has been scarcely found in this tumor, although there is some evidence suggesting expression of the beta-isoform. Unlike ER, progesterone receptor (PR) expression has been consistently observed. Immunohistochemical analysis of the two isoforms of ER has not been performed in this tumor. To characterize expression of ER isoforms with an immunohistochemical method. Expression of ER-alpha, ER-beta, and PR was analyzed by immunohistochemistry using isoform-specific ER and PR antibodies in paraffin-embedded tissue blocks from seven cases of PCN of the pancreas. Most patients were young females. ER-alpha and ER-beta were present in two and six tumors, respectively. PR was identified in six tumors. ER-beta expression predominates over the alpha-isoform in PCN of the pancreas. This finding supports the idea that previous negative results on ER expression were a consequence of the use of antibodies with no anti-beta activity. The role of ER-beta in the milieu of factors promoting the development and aggressiveness of PCN needs to be elucidated to address novel diagnostic and therapeutic approaches.