[785] Immunohistochemichal Analysis of Hypoxia-Inducible Protein 2 (HIG2), KSP-Cadherin and Carbonic Anhydrase IX (CAIX) Expression in Papillary, Clear Cell and Chromophobe Renal Cell Carcinoma

PB Illei, R Sharma, r Albadine, GJ Netto. Johns Hopkins Medical Institutions, Baltimore, MD

Background: Owing to overlapping morphologic features subset of renal cell carcinomas (RCC) cannot be classified into the major histologic types. There is a need for additional markers that would allow more accurate characterization of such tumors. HIG2 is expressed in fetal kidney and renal cortical carcinomas, KSP-Cadherin is found in basolateral membrane of renal tubular epithelium and colleting ducts as well as in chromophobe RCC and a subset of oncocytomas whereas CAIX expression was noted in clear cell RCC.
Design: We have performed immunohistochemistry for HIG2 (Novocastra, UK), CAIX (Novocastra, UK) and KSP-Cadherin (Cell Marque, USA) on tissue microarrays of 37 chromophobe RCC, 44 papillary RCC and 42 clear cell RCC that also contained 17 different normal tissues. Staining was evaluated semiquantitativly using a scoring system of 0-3+ for intensity and 1+ - 3+ for extent (<25%, 25-50%, >50%).
Results: CAIX positivity was seen in 39 of 41 (95%) clear cell RCC, in 42 of 44 (95%)papillary RCC and 0 of 37 (0%) chromophobe RCC. HIG2 expression was present in 33 of 42 (79%) clear cell RCC, 34 of 44 (77%) papillary RCC, and 8 of 37 (22%) chromophobe RCC. KSP-cadherin positivity was detected in 7 of 41 (17%) clear cell RCC, 38 of 44 (86%) papillary RCC and 31 of 35 (89%) of chromophobe RCC. In normal tissues, KSP-cadherin was only seen in kidney (tubules and collecting ducts), whereas weak HIG2 positivity was seen in liver, placenta, panceas, and in gallbladder and jejunal mucosa. Membranous CAIX staining was noted in gastric, gallbladder and small bowel mucosa, bile duct epithelium and skin.
Conclusions: The KSP-cadherin positive, HIG2 and CAIX negative phenotype was only seen in chromophobe tumors. On the other hand, a CAIX and HIG2 positive but KSP-cadherin negative phenotype strongly favors clear cell RCC. In addition, KSP-cadherin and HIG2 appear to be candidate markers for renal cell origin based on their staining pattern of benign tissues and renal cortical carcinomas.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 142, Tuesday Afternoon