The radioimmunoassay(RIA) has been used to measure epidermal growth factor(EGF) concentration in cancer tissues and non-malignant colorectal epithelial tissues surronding cancer from 40 patients with colorectal cancer. The results showed that EGF was significantly raised in colorectal cancer tissues than in normal epithelium (P<0.001). This implies that EGF in carcinoma tissue has its specific accumulation.