Grading dysplasia in colorectal adenomas by means of the quantitative binding pattern determination of Arachis hypogaea, Dolichos biflorus, Amaranthus caudatus, Maackia amurensis, and Sambucus nigra agglutinins

The current study deals with the setting up of a new tool that enables the benign versus the malignant nature of colorectal adenomas to be determined accurately. The 2 objectives are to determine (1) whether adenomas should, or should not, be included in a 2- or a 3-tier grading system, and (2) whet her severe dysplasias and carcinomas in situ share common or different biol ogical characteristics. The levels of expression of different types of glyc oconjugates were characterized in a series of 166 colorectal specimens, inc luding 14 normal, 90 dysplastic, and 62 cancerous cases. The glycoconjugate expressions were demonstrated for 5 lectins, namely, Arachis hypogaea (PNA ), Dolichos biflorus (DBA), Amaranthus caudatus (ACA), Maackia amurensis (M AA) and Sambucus nigra (SNA). The glycoconjugates demonstrated by these 5 l ectins belong to the family of the Thomsen-Friedenreich antigens. The bindi ng patterns of the 5 lectins were quantitatively determined by means of com puter-assisted microscopy. The quantitative data were submitted to discrimi nant analyses. Our results show that the specific glycochemical staining pa tterns could be identified unambiguously and without misclassification betw een benign (normal and low dysplasia) and malignant (ie, either as moderate /severe dysplasia, carcinoma in situ, or cancer) cases. The data also stron gly suggested that (1) dysplasias seem to be distinguishable in 2 instead o f 3 groups, that is, low versus moderate/severe (high); and (2) moderate/se vere dysplasias are biologically distinct from carcinomas in situ. The meth odology developed can be applied directly in routine diagnosis to identify moderate/severe dysplasia specimens already exhibiting features common to c arcinomas, and which therefore should be treated consistently in view of th e fact that our data strongly suggest that most moderate/severe dysplasias are still benign, whereas carcinomas in situ are real carcinomatous lesions . Copyright (C) 1999 by W.B. Saunders Company.