Expression of DBC1 and SIRT1 protein determined by means of immunohistochemistry in noncancerous mucosae (A, B) and the carcinomas (C–H).

<p>N, noncancerous mucosa; Ca, laryngeal or hypopharyngeal carcinoma; (−), negative immunostaining; (+), positive (low expression); (++), positive (high expression). Original magnification × 400. Expression of SIRT1 (I) and DBC1 (J) protein was determined by means of immunohistochemistry in carcinomas or adjacent noncancerous mucosae. Statistical analyses were performed with the Mann-Whiney 2-tailed test. All <i>P</i> values were considered significant at less than 0.05.