Expression of oestrogen receptor and oestrogen-inducible genes in pancreatic cancer

Background Previous studies have not been able to demonstrate convincingly whether the human pancreas expresses oestrogen receptor and whether there is any benefit from antioestrogen therapy in advanced pancreatic cancer. Methods Oestrogen receptor expression was assessed in normal human pancreas and pancreatic cancer tissue by enzyme immunoassay, Northern blot analysis, in situ hybridization and immunohistochemistry. The expression of the oestrogen-inducible proteins, progesterone receptor, pS2 and ERDS was also examined. Results A mean of 1.0 (range 0-2.4) fmol oestrogen receptor per mg protein was detected in normal pancreas and 0.5 (range 0-1.2) fmol mg(-1) in pancreatic cancer. Messenger RNA for oestrogen receptor was detected in both normal and cancerous pancreas. In situ hybridization and immunohistochemistry, however, failed to localize oestrogen receptor expression. Mean (range) expression of progesterone receptor in normal and neoplastic pancreas was 1.9 (0.5-3.5) and 2.5 (0.3-9.3) fmol mg(-1) respectively, pS2 and ERDS were also expressed in normal tissue and pancreatic cancer, and expression was localized to ductular epithelium. Conclusion The amount of oestrogen receptor detected in pancreatic tissue was small, and may account for previous difficulties in its detection. The extent to which it is functional in both the normal and malignant pancreas warrants further investigation.