Hepatocyte nuclear factor-1B(HNF-1B) in human urogenital organs, Its expression and role in embryogenesis and tumorigenesis

Molecules responsible for embryogenesis are often involved in tumorigenesis. Recent exhaustive cDNA microarray analyses in human neoplasms expanded knowledge of such molecules. Hepatocyte nuclear factor-1ß (HNF-1ß) is a homeobox transcription factor that functions as a homodimer or heterodimer with HNF-1a. In contrast to HNF-1a, HNF-1ß is very weakly expressed in the liver and is commonly expressed in the kidneys. During human embryonic stage, HNF-1ß plays an important role in organogenesis, especially of the urogenital system. In the human fetus, HNF-1ß expression is common in mesonephric duct derivatives and metanephros (permanent kidneys). HNF-1ß germline mutations cause malformations of these structures. Recent microarray analyses have disclosed that HNF-1ß is aberrantly up-regulated in clear cell carcinoma of the ovary, which is a carcinoma of müllerian nature, but which was initially misnamed “mesonephroma”. HNF-1ß is also expressed in ovarian endometriosis, which is a probable origin of clear cell carcinoma. On the other hand, HNF-1ß is downregulated in renal neoplasms, such as chromophobe cell carcinoma. In this review, we first summarize HNF-1ß expression in the developing urogenital system of the human embryo. Then, we describe the HNF-1ß status in human urogenital neoplasms and discuss its role in tumorigenesis