Diagnostic utility of p63/p40 in the histologic differentiation of salivary gland tumors: A systematic review

Abstract Background : Salivary gland tumors are heterogeneous group of neoplasms with complex clinicopathological behavior. These tumors often show an extremely diverse morphology and significant histological patterns making the diagnosis a difficult task. Due to the considerable differences in prognosis, treatment, and follow up, accurately distinguishing these histological mimickers is imperative. Aim : The aim of the present systematic review was to establish the diagnostic utility of p63/p40 immunostaining in histological differentiation of salivary gland tumors. Material and Methods : An electronic search was carried out using MEDLINE by PubMed, Scopus, Google scholar, Trip, Cochrane library and EMBASE databases. Articles, in which both p63 & p40 immunohistochemical expressions assessed were included for systematic review and their sensitivity and specificity were calculated. Risk of bias was analysed for each study using QUADAS-2 tool. Results : Ten eligible articles were included in the quantitative synthesis, which revealed a concordant positivity of p63 and p40 by nearly all cases of adenoid cystic carcinoma, pleomorphic adenoma and mucoepidermoid carcinoma while majority of polymorphous adenocarcinoma divulged discordant immunohistochemical expression (p63+/p40-). Conclusion : The current evidence supports that integrated immunostaining of p63/p40 is a valuable adjunct for discerning enigmatic salivary gland tumors with true myoepithelial and/or squamous differentiation.