The effect of incubation of rectal biopsies on measures of proliferation using proliferating cell nuclear antigen in comparison with 5-bromo-2- deoxyuridine

Abstract

Rectal epithelial cell kinetics are used as intermediate markers for colorectal cancer and relate to risk. In this study, measures of proliferation using direct immunohistochemistry for proliferating cell nuclear antigen (PCNA) were compared to in vitro labeling by bromodeoxyuridine (BrdUrd) and incubated biopsies that were later stained for PCNA (PCNA-I) in human rectal biopsies. The study group consisted of 20 sets of biopsies from 12 subjects participating in an intervention trial. Fresh nonincubated biopsies were fixed in methacarn and stained immunohistochemically for PCNA (clone 19A2). In parallel biopsies, BrdUrd was incorporated into the DNA of S-phase cells during a 2-h incubation a..