EXPRESSION OF LAMININ IN RENAL-CELL CARCINOMAS, RENAL-CELL CARCINOMA CELL-LINES AND XENOGRAFTS IN NUDE-MICE

We studied the expression of laminin (Ln) chains (alpha 1-alpha 3 beta 1-beta 3, gamma 1) in human renal-cell carcinomas (RCC), papillary re nal neoplasms (PRN) and oncocytomas, in RCC cell lines and their xenog rafts. In RCCs the basement membranes (BM) showed immunoreactivity for chains of Ln-1 (alpha 1-beta 1-gamma 1). Only in well-differentiated RCCs could vessel BMs be distinguished from those of carcinoma cell is lets. RCCs and oncocytomas also exhibited an abundant immunoreactivity for Ln beta 2 chain in both vessel and tumor cell BMs, while Ln alpha 2 chain was not seen in any renal tumors. In distinction from RCCs, P RNs presented a strong BM immunoreactivity for Ln alpha 3 and beta 3 c hains and for Ln-5, as well as lack of Ln beta 2 chain. A more variabl e reactivity for Ln-5 was seen in oncocytomas. As PRNs and oncocytomas have been suggested to originate from collecting ducts, it is notable that in normal human kidney, we could detect immunoreactivity for Ln- 5 and its chains only in BM of the tubules of the loop of Henle. In im munoprecipitation experiments, an abundant production of Ln-l, but not of Ln-5, was seen in cultured RCC cells, while in xenografts of the s ame cells BM-confined immunoreactivity for both Ln-1 and Ln-5 was seen . Ln beta 2 chain was produced by 2 of the 4 RCC cell lines in culture but was found only in 1 of the xenografted tumors. (C) 1996 Wiley-Lis s, Inc.