Antineoplastic effect of erbstatin on human mammary and esophageal tumors in athymic nude mice

The growth of MCF-7, a human mammary carcinoma, in athymic nude mice was inhibited by intraperitoneal administration of erbstatin for 14 days in combination with an iron chelator, foroxymithine, which inhibits the decomposition of erbstatin. Another human mammary carcinoma, Br-10, was not affected. Foroxymithine alone had no anti-tumor activity. In four esophageal tumors, erbstatin retarded tumor growth. There were no side-effects in any erbstatin-treated group. Levels of epidermal growth factor receptors were not changed throughout treatment with erbstatin at any dose. Erbstatin, a tyrosine kinase inhibitor, may have an antineoplastic effect against human mammary and esophageal tumors.