Lectin and mucin histochemistry as an aid to cancer surveillance in ulcerative colitis.

In a preliminary study, we assessed 10 lectins for the identification of dysplasia in colectomy specimens from patients with ulcerative colitis. Peanut agglutinin (PNA) binding was found in all cases of dysplasia. In the main study the relationship between PNA staining, high iron-diamine/alcian blue (HID-AB) histochemistry, and dysplasia was investigated in 115 pre-operative colonoscopic biopsies and the subsequent resection specimens from patients with ulcerative colitis complicated by carcinoma (n = 6) and patients undergoing proctocolectomy for failure of medical management (n = 8). Peanut lectin was of no value in the assessment of pre-malignant changes or cancer risk. However, the HID-AB stain appears to clarify the interpretation of less severe pre-malignant changes and may be usefully applied to the interpretation of colonoscopic biopsies for cancer surveillance in ulcerative colitis.