%0 Journal Article
%T CD133 Staining Detects Acute Kidney Injury and Differentiates Clear Cell Papillary Renal Cell Carcinoma from Other Renal Tumors
%A John D. Schwartz
%A Francis Dumler
%A Jason M. Hafron
%A George D. Wilson
%A Stacy C. Wolforth
%A Michele T. Rooney
%A Wei Li
%A Ping L. Zhang
%J ISRN Biomarkers
%D 2013
%R 10.1155/2013/353598
%X CD133 has recently been characterized as a progenitor cell marker in the kidney. However, the expression of this marker has not been thoroughly investigated in kidney injury and variants of renal tumors for pathology practice. We quantified CD133 expression in kidney biopsies from patients with acute renal failure and compared staining intensity with serum creatinine levels. CD133 expression levels were also evaluated in several subtypes of renal neoplasms. Normal adult renal parenchyma showed CD133 expression in parietal epithelium and in less than 5% of the epithelial cells in proximal and distal nephron tubules. However, CD133 was diffusely upregulated in the injured proximal and distal tubular epithelium and the CD133 expression scores in renal tubules were significantly correlated with serum creatinine levels. Amongst the renal tumors, CD133 was diffusely expressed in clear cell papillary renal cell carcinoma but was only focally present in other types of renal tumors. In summary, CD133 is a useful marker to detect renal tubular injury and to differentiate clear cell papillary renal cell carcinoma from other tumor types. 1. Introduction The kidney possesses a remarkable capacity for repair of the tubular epithelium in response to various forms of acute injury. Following a reversible injury, residual tubular cells proliferate and rebuild the renal epithelium [1, 2]. When injury is severe, damaged proximal tubules may dedifferentiate into a mesenchymal fibroblastic phenotype and produce the filament vimentin, a process observed in animal models [3]. Vimentin expression has also been described in injured tubular epithelium of human kidneys, supporting the notion that a similar dedifferentiation process also occurs in humans [4]. Epithelial dedifferentiation in renal tubules is known as the epithelial-to-mesenchymal transition (EMT), in contrast to its reversed process, the mesenchymal-to-epithelial transition, which occurs during normal embryogenesis [5]. EMT is a critical step of injury response during which transformed cells may be rendered vulnerable to malignant transformation via downregulation of critical tumor suppressor mechanisms. Additionally, an EMT-like process is thought to enhance the proliferative and metastatic potential of established tumors [5, 6]. CD133 is a pentaspan membrane protein that has been investigated for its potential utility as a stem cell marker in different adult organs and tumors [7]. It has been used to identify progenitor cells in the glomerular parietal epithelium [8¨C11] and undifferentiated cells in the
%U http://www.hindawi.com/journals/isrn.biomarkers/2013/353598/