A major goal in screening for definitive dysplasia is minimizing the false negative rate; therefore, we identified a threshold of p53 basal positivity (i.e., > 40%) at which 17.2% of UC-IIa crypts were interpreted as UC-III, and only 13.6% of UC-III crypts were missed from definitive dysplasia. This evidence concerns the gene TP53 and dysplasia.