TP53 and cancer: When compared with endoscopic biopsy results, this yielded a positive predictive value of 31% (12 of 39 patients) for high-grade dysplasia or intramucosal cancer and 44% (17 of 39) for any grade of dysplasia; as expected, patients with both aberrant p53 expression and atypia were most likely to have high-grade dysplasia or cancer (seven [64%] of 11 patients).