TGFA and renal carcinoma: Inverse expression of EGFR and c-erbB-2 in kidney carcinomas has been reported.14In vitro, TGF-α has a stimulating effect on c-erbB-2 and not on EGFR, thus suggesting a distinct modulatory effect.15 It has also been reported that a reduction in TGF-α concentration does not alter the growth rate of the normal pharyngeal epithelium, but reduces the growth rate of the SCC.16 We can hypothesize that, during carcinogenesis, at least part of the selective advantage of the SCC clone is obtained through reduction in c-erbB-2 expression and increased activity of EGFR expression.