Expression of Epidermal Growth Factor Receptor: Risk Factor in Uveal Melanoma

PURPOSE. To investigate the prognostic significance of the expression of epidermal growth factor receptor (EGFR) in uveal melanoma. EGFR is a transmembrane glycoprotein, and its expression has been correlated with the development of metastases in various malignancies. METHODS. Frozen sections from 22 primary uveal melanomas were examined for EGFR expression by a three-step immunoperoxidase staining, using a mouse anti-human EGFR IgG2b monoclonal antibody. The results were compared with patient survival and clinical and histopathologic parameters. RESULTS. EGFR expression could not be determined on one tumor due to excessive pigmentation. Two patients died of causes unrelated to melanoma, and two patients were lost to follow-up. Out of 21 tumors, six tumors showed immunoreactivity for EGFR. Five of these six patients (83%) died due to metastases, compared with 2 (17%) of 12 patients with no EGFR expression (Kaplan-Meier analysis P = 0.0004). EGFR-positive tumors tended to have a greater tumor prominence and a higher mitotic rate. CONCLUSIONS. The expression of EGFR was significantly correlated with death due to metastatic disease and therefore can be regarded as an important prognostic factor in human uveal melanoma.