The Expression of Epidermal Growth Factor Receptor and Transforming Growth Factor Alpha in Renal Cell Carcinoma

Immunohistochemical stains using antibody to epidermal growth factor receptor (EGFR) and transforming growth factor alpha (TGF-alpha) were applied to 67 cases of renal cell carcinoma retrieved from the files of the Division of Surgical Pathology. The 64 patients (33 females, 31 males) ranged in age from 35 to 87 years (mean, 61 years). Two patients had more than one renal carcinoma included in this study. Fifty-seven cases (85%) expressed EGFR, with staining largely confined to the cell membrane. Staining intensity was directly correlated with tumor grade (P = 0.02, T test), size (P = 0.04), and stage (P = 0.01). Those cases with more intense EGFR staining also appear to have shorter patient survival than those showing less intense staining (43 mo versus 63 mo, P = 0.05). Forty-nine cases (73%) expressed TGF-alpha in a distribution similar to that of EGFR. There was no significant correlation between TGF-alpha staining intensity and tumor size, stage, or grade. When the tumor expressed either EGFR or TGF-alpha but not both proteins, average patient survival was 38 months, while the average survival of those patients whose tumors expressed both EGFR and TGF-alpha was 61 months (P = 0.04). Three of eleven cases, all of which expressed EGFR, were felt to show EGFR gene amplification using a modification of the differential polymerase chain reaction on archival, formalin-fixed, paraffin-embedded tissue. EGFR and TGF-alpha likely play a role in the progression of renal cell carcinoma, and their coexpression may have favorable prognostic implications.