ABSTRACT
Objective To study the expression of P63 in 76 patients with thymic epithelial tumors (TET, including thymomas and thymic carcinomas) and its role in pathological diagnosis of TET based on World Health Organization classification. Methods Immunohistochemistry (SP method) was used to detect P63 expression in 76 different subtypes of TET tissues. The initial diagnostic results, further diagnosis results and diagnostic results considering P63 expression were analyzed and compared. Results The further diagnosis results identified 9 cases of misdiagnosis (mainly AB and B subtypes) and 3 uncertain cases. Different degrees of P63 expression (located in the nuclei) was observed in 72 cases, and different subtypes had different expression patterns. The diagnostic results considering P63 expression were more accurate than those not considering P63 expression (TET, P = 0. 017 and thymoma, P = 0. 032, respectively). Detection of P63 expression helped to confirm the diagnosis of the 3 uncertain cases according to the further diagnosis results. Conclusion Considering that P63 expression can help to better differentiate the subtypes of thymoma, it should be used as a routine marker for clinical diagnosis, especially for AB and B subtype thymoma.