Growth-inhibitory effects of epidermal growth factor on human breast cancer and carcinoma of the esophagus transplanted into nude mice.

The present work was performed to clarify the effects of epidermal growth factor (EGF) on the growth of human breast cancer and carcinoma of the esophagus. Human breast cancer MX-1, UM-1, and esophageal cancer ES-4 were transplanted to the subcutaneous tissue of nude mice. Human EGF (2 micrograms) was injected locally into the subcutaneous tissue surrounding the tumor. The tumor growth was followed for 7 days after treatment, and the estimated tumor weight, tumor doubling time, tumor growth curve, tumor growth rate, and results from histologic examination were used to evaluate the effects of EGF on the growth of tumors. We investigated the dose effect on the growth of these tumors using various concentrations of EGF. We also studied the EGF receptor status of these transplanted tumors and its effect on the influence of EGF treatment. A growth-inhibitory effect was noted in these three tumors with 2 micrograms of EGF. EGF inhibited growth of ES-4 tumor in a dose-dependent manner. Treatment with 2 ng of EGF or saline did not inhibit growth. However treatment with 20 ng or 200 ng of EGF inhibited growth in proportion to the concentrations. All tumors were positive by the EGF receptor binding assay. The efficacy of EGF treatment correlated with EGF receptor levels. EGF receptor levels were also influenced by EGF treatment. These results suggest that human EGF showed an anti-tumor effect on MX-1 and UM-1 breast cancer and also on ES-4 esophageal cancer.