The use of early and midpoint adenoma-carcinoma sequence biomarkers in prediction of neoplastic progression in...

Since significant neoplasia after initial colonoscopy is low, we conducted this pilot study to compare the predictive role for colorectal neoplasia recurrence of anti-DCC with that of Adnab-9 binding to colonic effluent of high-risk patients. DCC and Adnab-9 effluent ELISA were performed at baseline colonoscopies. The results of follow-up colonoscopies were reviewed. To ensure specificity, immunohistochemistry and Western blot was performed with anti-DCC and for Adnab-9 where optimal fixation times were also evaluated. Mean follow-up was 2.6 years. Of 21 patients, 6 of 10 who progressed to CRN and 2 of 11 who did not had a positive Adnab-9 ELISA result (P=0.08). Despite an initial good correlation with Adnab-9 ELISA results in a smaller dataset, we were unable to obtain consistent subsequent DCC immunohistochemistry or Western blot data using antibody from two different sources. However, the original dataset of Adnab-9 results was reproducible on repetition of the ELISA with a larger set of samples that included this initial dataset and optimal fixation time was 20 min. We conclude that Adnab-9 appears to be a promising prognostic marker for neoplasia in the high-risk population. Industry standards need to be developed for DCC monoclonal antibodies that may have similar utility.