POLYMORPHIC EPITHELIAL MUCIN (PEM) EPITOPES IN THE ESTIMATION OF THE SEQUENCE OF NEOPLASTIC CHANGES IN COLON ADENOCARCINOMA

Aims: The relation between the expression of PEM epitopes and the sequ ence of neoplastic changes in individual patients with colon adenocarc inoma was investigated. Methodc: Immunohistochemical staining was perf ormed using four monoclonal antibodies to PEM epitopes (139H2. 140C1, 115D8, 115F5) on tissue sections from frankly malignant lesions adjace nt mucosa, colonic mucosa taken 1 cm and 5 cm from the lesion and norm al control mucosa. Results: A clear correlation between PEM expression and the site of mucosa sampling was demonstrated. The expression of P EM molecules defined by all Studied monoclonal antibodies was highest in colon adenocarcinoma, similar but slightly weaker in adjacent mucos a and colon mucosa taken 1 cm from the frankly malignant lesion, lowes t in mucosa 5 cm from the lesion, and virtually absent in control norm al colonic mucosa. Conclusions: The immunological changes could be one of the first signs of a premalignant process and the estimation of PE M epitopes could show some cellular abnormalities not detectable by st andard pathomorphological criteria.