Kidney Injury Molecule-1 (KIM-1) Expression in Renal Clear Cell Carcinoma
I de Torres, M Vila, E Trilla, ME Semidey, S Planas, A Meseguer, J Morote, S Ramon y Cajal. Vall de Hebron University Hospital, Barcelona, Spain
Background: Kidney Injury Molecule (KIM-1) is a transmembrane glycoprotein type 1 overexpressed in the epithelium of proximal tubules of human kidney under ischemia or nephrotoxic injury as well as in tubulointestitial diseases and several policystic renal diseases. Previous studies suggest that this molecule could be an specific and sensitive biomarker of renal clear cell carcinoma (RCCC) and their metastases.
Design: A serie of 100 patients with diagnosis of RCCC in our Hospital collected between 2000 and 2004 were studied. Tissue Microarrays (TMAs) were designed . For each case tumor tissue and normal tissue three representative areas were selected on the slides and then removed from the corresponding paraffin block, with a punch of 1,2 mm. KIM-1 polyclonal antibody was used for the inmunohistochemical study (1: 50 dilution). The expression was evaluated using a semiquantitative method ranging 0-300 (HScore). The results were analysed by means the SPSS Data Analysis Program 13.0.
Results: The expression of KIM-1 in RCCC was diffuse in cytoplasms with mild to strong intensity. The univariated and multivariated analysis of KIM-1 expression with the variables Frhman grade, necrosis and microvascular permeation , no observed significative correlation. Clinical stratification in low, middle and high groups of risk (Leivobitch 2003 classification) and ranked of Hscore inmunostain (<100, 100-200 and >200) demonstrated a significant correlation in the low risk group and Hscore <100 in order the cancer specific survival and disease-free survival (p=0.039).
Conclusions: Therefore KIM-1 coul be considered as a tumor supressor gene in some renal cell carcinomas . A low KIM-1 expression could be a marker to identify a subset of low risk renal clear cell carcinomas with worse prognosis. Patients with clinical low risk RCCC (pT1a, grades 1-2, without necrosis and low levels of calcium in serum) and KIM-1 expression under 100, show an increase number of recurrences.
Category: Genitourinary (including renal tumors)
Tuesday, March 10, 2009 9:30 AM
Poster Session III # 74, Tuesday Morning