A radioimmunoconjugate consisting of a murine IgG2a monoclonal antibody directed against the human epidermal growth factor receptor (EGFR) labeled with iodine I 125 with potential antineoplastic activity. Iodine I 125 anti-EGFR-425 monoclonal antibody binds specifically to the epidermal growth factor receptor (EGFR). Upon binding to EGFR-expressing tumor cells, this agent is internalized, selectively delivering a potentially cytotoxic dose of gamma radiation. EGFR is a receptor tyrosine kinase that may be overexpressed on the cell surfaces of various solid tumors. Check for active clinical trialsusing this agent.