Tissue CA-19.9 content in colorectal adenomas and its value in the assesment of dysplasia

Background: occasionally, the risk of malignant transformation may be difficult to establish in adenomatous polyps due to the fact that they contain areas with variable grades of dysplasia. A measurement of tissue tumor markers may be useful to recognize these adenomas. Objectives: the aims of this study were: to establish firstly the relationship between carbohydrate antigen 19.9 (CA-19.9) content in the colorectal mucosa and the characteristics of polyps, and secondly, the diagnostic value of the former’s measurement. Patients and methods: tissue CA-19.9 concentration was measured in 155 colorectal samples obtained from 145 patients (21 normal mucosa; 113 adenomatous polyps; 21 adenocarcinoma). Cytosol CA-19.9 content was determined by enzyme-linked immunoadsorbant assay, and the measurement of this protein was achieved by quantitative assay. Tissue samples were also processed for histological examination. Results: we demonstrated that CA-19.9 levels in adenomatous polyps and adenocarcinomas were significantly higher than in the normal mucosa. These levels varied significantly according to polyp size, histological type, and grade of dysplasia. CA-19.9 contents were higher in polyps with a high risk of malignant transformation than in those with a low risk of severe dysplasia. The cut-off value 214 U/mg of protein properly differentiated both types of risk. The area under the receiver operating characteristic (ROC) curves showed that cytosol CA-19.9 levels allow classifying polyps according to their histological features. Conclusions: we concluded that the measurement of CA19.9 content in adenomatous polyps may be useful to classify these tumors and confirm the feasibility to separate adenomas into two groups: low and high risk of malignant change.