EXPRESSION OF FAS IN RENAL-CELL CARCINOMA

We have investigated whether the Fas-mediated cell death pathway is fu nctional in renal cell carcinoma, The expression of Fas in surgical sp ecimens and cell lines of renal cell carcinoma was examined. Fas expre ssion was positive in six out of 18 tumors measured by flow cytometry and was prominent in advanced tumors, Three out of the six Fas-positiv e tumors had already metastasized at the time of surgery. A significan t correlation was found between the tumor volume and the percentage of Fas-positive cells in a tumor (r = 0.70, P = 0.0007), Fas-positive tu mors were larger than Fas-negative tumors [mean tumor volume (ml) +/- SD, Fas(+), 265.6 +/- 136.8; Fas(-), 65.8 +/- 80.9, P = 0.0012], All h uman renal carcinoma cell lines tested (ACHN, Caki-1, SMKT-R-2, SMKT-R -3 and SMKT-R-4) expressed Fas abundantly, as Fas-positive cells accou nted for >50% in all cell lines by flow cytometry. Treatment with anti -fas antibody caused apoptosis in Fas-positive renal cell carcinoma ce ll lines, However, the effectiveness of apoptosis induction in individ ual cell lines was not correlated with the level of Fas expressed, The se data suggest that Fas targeting may be a therapeutic option for tre atment of advanced renal cell carcinoma which is refractory to either chemotherapy or irradiation.