Epidermal growth factor receptor and transforming growth factor alpha expression in papillary and nonpapillary renal...

Papillary renal carcinomas are a cytogenetically unique subset of renal carcinomas that have been reported to be clinically less aggressive. We have examined 19 papillary tumors for immunohistochemical expression of the epidermal growth factor receptor (EGF-R) and its ligand, transforming growth factor alpha (TGF-alpha). EGF-R and TGF-alpha expression was also studied in 149 nonpapillary tumors and 7 mixed papillary/solid tumors. EGF-R and TGF-alpha expression were compared to histology, stage, metastatic behavior, and survival. Formalin-fixed, paraffin-embedded nephrectomy specimens collected between 1977 and 1986 were stained with antibodies to EGF-R and TGF-alpha. Patients with papillary tumors were found to present with earlier stage disease and had significantly longer survival. Papillary tumors had a significantly lower rate of EGF-R positivity than solid pattern tumors (21% versus 73%, P < 0.001). Intermediate or strong cell membrane immunoreactivity for EGF-R was associated with high tumor grade and poor disease-specific survival. EGF-R positivity in the primary tumor was associated with the presence of metastatic disease and with metastatic spread to lung versus bone. Tumor parenchymal TGF-alpha staining was present in 50% of the cases and was not associated with stage or grade. Unrelated to tumor parenchymal TGF staining, tumor vessels stained for TGF-alpha in 56% of the cases. Vessel TGF-alpha staining was absent in papillary tumors (P < 0.001). The improved clinical behavior of papillary tumors as compared to nonpapillary renal tumors may be related, in part, to their relatively lower levels of EGF-R expression.