Changes in composition of mucin in the mucosa adjacent to carcinoma of the colon as compared with the normal: a biochemical investigation.

Fifteen surgical specimens from patients with carcinoma of the colon and rectum were studied. Scrapings from normal mucosa distant from the tumour and from macroscopically normal mucosa adjacent to the tumour (;transitional') were used for chemical estimation of hexosamines, sialic acid, and proteins. The presence of hexosamines and sialic acid was confirmed in both normal and transitional mucosa. Transitional mucosa showed increased levels of total hexosamines and sialic acid as compared with the normal and this was accompanied by an increase in neuraminidase-sensitive sialic acids. The present data have been compared with previous histochemical and autoradiographic studies and it is suggested that the changes described in the transitional mucosa are transformations representing an early stage of carcinogenesis.