RT Journal Article SR Electronic T1 Expression of SET, an inhibitor of protein phosphatase 2A, in renal development and Wilms' tumor. JF Journal of the American Society of Nephrology JO J. Am. Soc. Nephrol. FD American Society of Nephrology SP 1873 OP 1880 DO 10.1681/ASN.V9101873 VO 9 IS 10 A1 Carlson, S G A1 Eng, E A1 Kim, E G A1 Perlman, E J A1 Copeland, T D A1 Ballermann, B J YR 1998 UL http://jasn.asnjournals.org/content/9/10/1873.abstract AB The human gene set was originally identified as a component of the set-can fusion gene produced by a somatic translocation event in a case of acute undifferentiated leukemia. In the developing kidney, set was highly expressed in the zone of nephron morphogenesis. Recently, SET was shown to be a potent and specific inhibitor of protein phosphatase 2A, a family of major serine/threonine phosphatases involved in regulating cell proliferation and differentiation. The current study sought to define further the role of SET in the regulation of renal cell proliferation and tumorigenesis. The mRNA encoding SET was expressed at much higher levels in transformed human and rodent cell lines than in cultured renal epithelial and primary endothelial cells. Consistent with a role for SET in cell proliferation, set mRNA expression was markedly reduced in cells rendered quiescent by serum starvation, contact inhibition, or differentiation. Previous findings during renal development were extended by demonstrating that SET protein expression is also much greater in developing rat and human kidney than in fully differentiated, mature kidney. Finally, high levels of set mRNA and SET protein expression were found in Wilms' tumor, but not in renal cell carcinoma, adult polycystic kidney disease or in transitional cell carcinoma.