Mucin profiles in ulcerative colitis with dysplasia and carcinoma.

Mucin secretion was assessed in Crohn's colitis, in ulcerative colitis with regeneration, dysplasia and carcinoma and in non-colitic adenocarcinoma. The high iron diamine-alcian blue (HID-AB) and periodate borohydride-saponification periodic acid Schiff (PB-KOH-PAS) techniques were used to demonstrate sulphomucins and sialomucins, and O-acylated sialomucins respectively. There was mucosal hyperplasia and increased sialomucin secretion in Crohn's disease, quiescent and active ulcerative colitis. In colitis with carcinoma inflamed mucosa away from the tumour had increased sialomucins as had colitis with dysplasia. They did not differ statistically from each other or from colitic controls without cancer. Dysplastic crypts frequently secreted sulphomucins and the increased sialomucins were in transitional-like glands in the surface fronds or adjacent to the dysplasia. A comparative study of the HID-AB technique gave total correct qualitative allocation of individual quantitatively assessed crypts. Routine HID-AB staining did not aid the recognition of dysplasia in ulcerative colitis. With the PB-KOH-PAS technique colorectal adenocarcinoma showed a significant diminution in O-acylated sialomucins compared with its adjacent mucosa. Mucosal dysplasia in ulcerative colitis displayed a similar trend in O-acylated sialic acid variants, differing with respect to age-and sex-matched colitic controls. The PB-KOH-PAS technique may be of help in assessing mucin secretion in ulcerative colitis as a guide to the evolution of malignancy.