HETEROGENEITY OF RENAL-CARCINOMA

Monoclonal antibodies were used to study the expression of three recen tly characterized basement membrane components and two carbohydrate an tigens in 11 renal-cell carcinomas, using immunohistological and bioch emical techniques. The expression of several site-specific kidney anti gens in renal-cell carcinoma were studied to determine the origin of t he carcinoma and if it is possible further classify this type of carci noma. Tubulointerstitial nephritis antigen (TIN) and two alpha-chains of type IV collagen, alpha 1(IV) and alpha 3(IV) were studied. In addi tion the expression of carbohydrate antigens Le(x) and SLe(x) which al so exhibit site-specific distribution were characterized. Le(x) and SL e(x) antibodies stained the majority of the tumours. TIN was expressed in 9 of 11 tumours, the alpha 1(IV) chain was present in all 11, and the alpha 3(IV) chain in two of the 11 tumours. Interestingly, the two alpha 3(IV)-positive tumours were the same two that were negative for TIN. In normal tissue alpha 3(IV) is found in distal tubules while TI N is found in proximal tubules. Our results are consistent with earlie r observations that the proximal tubule is the origin of most renal-ce ll carcinomas, but the results also indicate that renal-cell carcinoma may originate from the distal tubule.