1996 Volume 87 Issue 9 Pages 1120-1126
(Background) Monoclonal antibodies (mABs) against urinary proteins originated from renal tubules were obtained in order to find a possible tumor marker for renal cell carcinoma.
(Methods) Urine samples were collected from healthy adult males. After removal of Thamm-Horsfall protein (THP) by sodium chloride precipitation, supernatant urine was ultrafiltered, thus, THP-free urinary proteins were obtained. Then, proteins of plasma origin were removed by circulating the urinary proteins through an affinity column which contained immobilized rabbit anti-human whole serum immunoglobulins. BALB/c mice were immunized with the THP- and plasma protein-free urinary proteins. The spleen cells were fused with mouse myeloma cells. Hybridomas were screened by indirect immunofluorescence of fresh frozen kidney tissue sections using culture supernatants.
(Results) Five hybridomas producing mAbs which reacted with renal tubular segments were established. One mAb reacted strongly with distal renal tubules. Using this mAb, formalin fixed and paraffin embedded sections of 39 renal cell carcinomas were stained by immunoperoxidase method. Twenty-six of the 39 cancer tissues (66.7%) were stained positive. According to the histological classification, positive staining rate of clear cell subtype, granular cell subtype and mixed subtype was 75% (6/8), 80% (8/10) and 66.7% (6/9), respectively. According to the tumor grade, positive staining rate of G1, G2, G3 was 66.7% (6/9), 71.4% (15/21) and 55.5% (5/9), respectively.
(Conclusion) These findings indicate that most of renal cell carcinomas were originated from common precursor cells for both proximal and distal tubules, because normal proximal tubular cells were not stained by the mAb.
