Differential expression of frpHE: A novel human stromal protein of the secreted frizzled gene family, during the endometrial cycle and malignancy

By using the differential display technique to identify genes that are diff erentially expressed in human endometrial carcinoma compared with normal en dometrium, we have cloned frpHE, a novel member of the secreted frizzled ge ne family. By in situ hybridization, we have determined that frpHE is expre ssed by mesenchymal cells but not by epithelial cells. The expression of fr pHE is modulated during the endometrial cycle: it is expressed in the strom a of proliferative endometrium and not significantly detectable in secretor y or menstrual endometrium, suggesting that frpHE is under hormonal regulat ion. In addition, the expression of frpHE mRNA is markedly up-regulated in the stroma of endometrial hyperplasia and carcinoma and in the stroma of in situ and infiltrating breast carcinomas. Injection of frpHE mRNA in Xenopu s embryos inhibited the Wnt-8 mediated dorsal axis duplication. These resul ts indicate that frpHE functions as a regulator of the Wnt-frizzled signali ng pathway and is involved in endometrial physiology and carcinogenesis.