Ninety-three polypectomized cases from the sigmo-rectal region were examined by lectin histochemistry. On the apical surface, the UEA-1 binding sites were positive in 24/29 carcinomas and in 25/62 adenomas; while the GSA-1 binding sites were positive in 16/29 carcinomas and in 0/62 adenomas. In 2 non-neoplastic polyps, only one case was UEA-1 positive; none was GSA-1 positive. In neighbouring regions, adenomas adjacent to carcinomas were UEA-1 positive in 9/27 cases and GSA-1 positive in 3/37 cases. Thus, the GSA-1 binding sites were expressed more specifically on carcinomas. In the Golgi area, none of the polyps was UEA-1 positive while most of the cells showing GSA-1 positivity were apt to do so within the cells without showing GSA-1 positivity on the apical surface. There were no correlations between the positive rate of the lectin binding sites on the apical surface and the stage of cancer development or the histology of the adenoma on which a cancer developed. The meaning of this restricted appearance of the GSA-1 binding sites on the cancer cell surface was discussed in relation to observations previously reported in the literature.