Expression of Novel Markers Human Kidney Injury Molecule-1 (Hkim-1), S100A1 and Napsin A in the Differential Diagnosis of Renal Cell Carcinomas (RCC) with Clear and Papillary Features
Manju Aron, Mitual Amin, Ping Zhang, Mariza DePeralta-Venturina, Sambit K Mohanty, Sijian Wang, Mahul B Amin. Cedars-Sinai Medical Center, Los Angeles, CA; William Beaumont Hospital, Detroit
Background: The differential diagnosis of RCC with clear and papillary features includes the well established subtypes such as clear cell RCC, papillary (pap) RCC and recently recognized rarer subtypes including clear cell-papillary RCC (CC-PRCC) and translocation associated RCC. Expression of newer markers of RCC including hKIM-1, Napsin A, and S100A1 have not been reported in CC-PRCC and translocation associated RCC. hKIM-1 is a type I transmembrane glycoprotein expressed in injured renal proximal tubules but not in the normal nephron. S100A1 is a calcium-binding protein of the EF-hand family which is expressed in the entire nephron except the glomerulus. Napsin A is an aspartic proteinase that is expressed in type II pneumocytes, and the proximal and distal convoluted tubules of the kidney. This study was conducted to evaluate the utility of these markers in the differential diagnosis of RCC with clear and papillary features.
Design: 33 RCCs [translocation associated RCC (n=7), CC-PRCC (n=12), clear cell RCC (n=7) and pap RCC (n=7)] were included in the study. Representative sections were studied to confirm the histological diagnosis and sections from the tumor were stained with hKIM-1, S100A1 and Napsin A. The Kim-1 staining was graded as: 0=absent, 1+=<10%, 2+=11%- 50%, 3+=>50%. Napsin A and S100A1 stains were semiquantitatively graded as: 0 =absent; 1=weak, <25%; 2= moderate, 25-50%; 3=strong,> 50%.
Results: The results of the study are outlined in the table with immunoreactivity reported as percent positive.
|Clear cell RCC||100||100||86∗|