Protein levels of PAI-1, are increased in the transition from quiescent colitis to high grade dysplasia and carcinoma. Representative images immunofluorescent staining of quiescent epithelium (top left), high-grade dysplasia (middle left) and carcinoma (bottom left) using an antibody targeting PAI-1. Exposure time = 300 msec. Top right, mean fluorescent intensities with individual observations (each individual is a distinct color/shape) and mean ± SEM (n = 11 quiescent colitis, n = 10 high-grade dysplasia, n = 9 carcinoma). Each observation represents the average fluorescent intensity from five randomly selected fields.*p<0.05 compared to quiescent colitis. Bottom right, staining without (left) and with (right) neutralizing peptide displays specificity of the antibody.