[Typing of colorectal epithelium by lectin histochemistry: expression of T glycoepitope]

The current study deals with the setting up of a new tool that enables the benign versus the malignant nature of colorectal epithelium to be determined early and accurately. The objective is to determine a different biologic characteristic between normal and malignant colorectal tissue, which is the site and the level of expression of the T glycoepitope (Thomsen-Friedenreich antigen). It was characterized in a series of 62 colorectal samples, including 31 normal (without pathologic lesion) and 31 cancerous (mostly moderately or poorly differentiated) tissue sections. The glycoconjugate expression was demonstrated by lectin-histochemistry, using PNA lectin. The binding patterns of the lectin were determined in both columnar and goblet cells, from normal and malignant colorectal tissue. The results show that specific and different glycochemical staining patterns could be identified between benign and malignant epithelium. The data of the cytostructural localization were submitted to statistical analyses, which strongly suggested the association between the patterns of expression of the T antigen and the degree of the tissue differentiation. The methodology developed can be applied directly in routine diagnosis and it has an important prognostic value.