Pharmacokinetic and biodistribution studies in BALB/c nude mice demonstrated a long serum half-life and excellent and specific targeting properties for tumours containing de2-7EGFR or amplified EGFR. The prolonged and superior tumour uptake observed for 111In-ch806 compared to the l25I-conjugate suggest that ch806 is rapidly internalised following binding with concomitant catabolism and excretion of the radiohalide from the tumour cell. Here, EGFR is linked to neoplasm.