COMPARISON OF RECTAL MUCOSAL PROLIFERATION MEASURED BY PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IMMUNOHISTOCHEMISTRY AND WHOLE CRYPT DISSECTION

Rectal mucosal proliferation has been promoted as an intermediate mark er for risk of colorectal neoplasia, Proliferating cell nuclear antige n (PCNA) immunohistochemistry has become a standard method to measure cell proliferation, Whole-crypt dissection may provide a technically s impler method for determining proliferation within an entire crypt, We conducted a study to assess the reliability (reproducibility) of whol e-crypt dissection in 10 subjects, and we compared whole-crypt dissect ion to PCNA immunohistochemistry in 91 subjects, Reliability of whole- crypt dissection,vith the subject as the unit of observation was excel lent, The intraclass correlation coefficient for subjects was 0.93, Bi opsy-to-biopsy reliability was lower (r = 0.86) and crypt-to-crypt rel iability lower still (r = 0.35), There was poor correlation between me asures of proliferation index using the two techniques (Kendall's tau = 0.13; P = 0.08), Compartment analysis based on the percentage of the total number of labeled cells appearing in each crypt quartile also d id not demonstrate a significant correlation between the two measures, We conclude that PCNA labeling index and whole-crypt mitotic count ar e not comparable measures of rectal mucosal proliferation.