自1965年Gold与Freedman发现胃肠道肿瘤癌胚抗元(Carcinoembryonic antigen以下简称(CEA)升高以来,1969年Thompson等用放射免疫测定法(KIA)测定血清,发现大肠癌CEA升高的阳性率为97％,以后Moore,Lo Gerfo,Reynoso等报告大肠癌CEA的阳性率分别为91,86与83％。但1971和1974年较大规模的检查,则阳性率降低到72％。1975 Since Gold and Freedman discovered in 1965 that Carcinoembryonic antigen (CEA) has risen in the gastrointestinal tract tumor, 1969 Thompson et al. used serum radioimmunoassay (KIA) to measure sera and found that the colorectal cancer CEA increased positive. The rate was 97%, and Moore, Lo Gerfo, Reynoso et al reported that the positive rates of CEA in colorectal cancer were 91, 86, and 83%, respectively, but in 1971 and 1974, the positive rate was reduced to 72%.