Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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The epidermal growth factor receptor (EGFR) is an attractive target for the design of radiotherapeutic agents for breast cancer because it is present on almost all estrogen receptor-negative, hormone-resistant tumors with a poor prognosis. In this study, we describe the antitumor effects and normal tissue toxicity of the novel Auger electron-emitting radiopharmaceutical (111)In-labeled diethylenetriaminepentaacetic acid-human epidermal growth factor ((111)In-DTPA-hEGF) administered to athymic mice bearing EGFR-positive human breast cancer xenografts. ⋯ (111)In-DTPA-hEGF exhibited strong antitumor effects against MDA-MB-468 breast cancer xenografts overexpressing EGFR. The highest tumor localization, radiation-absorbed doses, and growth inhibition were achieved for small, nonestablished tumors, suggesting that the radiopharmaceutical may be most valuable for the treatment of small-volume metastatic breast cancer or occult micrometastases in an adjuvant setting.