Mucin histochemistry of the lower gastrointestinal tract.

Variations in the mucin secretion pattern in the mucosal lining of the colon and rectum have been studied. Mucins have been differentiated histochemically as neutral mucins, sialomucins and sulphomucins, using alcian blue/PAS and HID/alcian blue techniques. In the normal colonic mucosa, the goblet cells secrete predominantly sulphomucins with small amounts of sialomucins. Twenty one cases with benign lesions showed varying patterns of mucin secretion. In the 35 cases with adenocarcinoma studied, the transitional mucosa adjacent to the lesion showed a reversal of mucin secretion pattern, with an increase in sialomucins and a marked decrease in sulphomucins, suggesting a reaction to neoplasia.