TENASCIN AND FIBRONECTIN ISOFORMS IN HUMAN RENAL-CELL CARCINOMAS, RENAL-CELL CARCINOMA CELL-LINES AND XENOGRAFTS IN NUDE-MICE

We studied the expression of tenascin (Tn) and isoforms of fibronectin (Fn) in human renal cell carcinomas (RCC) and oncocytomas, in RCC eel lines and in their s.c. implanted xenografts in nude mice. In well-di fferentiated RCCs and oncocytomas extra-domain A (EDA)-Fn and Tn immun oreactivities were confined to the basement membranes and blood vessel s, while in less-differentiated RCCs they were also widely seen in the stroma, correlating with the morphological differentiation of the tum or. Expression of EDB-Fn and oncofetal (onc)-Fn was very scarce in mos t of the RCCs and oncocytomas. Western blotting results demonstrated t he predominance of the M(r) 190,000 Tn subunit in most RCCs. Among the 4 RCC cell lines, 3 showed Tn in the extracelldar matrix. As xenograf ts, they formed moderately or poorly differentiated tumors, with abund ant Tn. Three of the RCC cell lines also showed secretion of EDA-Fn an d 2 of them secretion of onc-Fn and EDB-Fn into the culture medium, wh ile in xenografts there was a strong expression of all Fn isoforms. In xenografts, the expression of Tn closely recapitulated that seen in c linical tumors and in the eel lines in vitro while the expression of F n isoforms in cultured cells and their xenografts was highly discordan t. (C) 1995 Wiley-Liss, Inc.