EXPRESSION OF ESTROGEN-RECEPTOR AND ESTROGEN-INDUCIBLE GENES PS2 AND ERD5 IN LARGE-BOWEL MUCOSA AND CANCER

Since there is a preponderance of large bowel cancer in males, both in humans and in experimental models, and hormone replacement therapy is protective, a role for sex steroid hormones in the pathogenesis of th is neoplasm seems likely. Evidence of functional oestrogen receptor ha s been looked for in large bowel mucosa and cancer. Expression of oest rogen receptor, and of the oestrogen-inducible receptor-associated gen es pS2 and ERD5, was sought. Oestrogen receptor mRNA was detected in c ancers and paired normal mucosae in equal amounts. In situ hybridizati on identified stromal cells above the muscularis mucosae that were pos itive for oestrogen receptor mRNA, pS2 mRNA was also detected, with a signal intensity significantly higher in normal mucosa compared with c ancers, whereas the reverse was seen with ERD5 mRNA levels. pS2 and ER D5 mere expressed in epithelium, with the former in a greater amount i n distal colon and rectum than proximal colon. Although oestrogen-indu cible and receptor-associated genes are expressed in large bowel mucos a, their expression does not correlate with oestrogen receptor. (C) 19 98 John Wiley & Sons, Ltd.