BRCA1/2 Mutations in Salivary Pleomorphic Adenoma and Carcinoma-ex-Pleomorphic Adenoma.

Objectives: It is hypothesized that carcinoma-ex-pleomorphic adenoma (Ca-ex-PA) is malignant from the beginning or is a malignant transformation of a recurrent or a long-standing pleomorphic adenoma (PA). The accumulation of genetic instabilities is suggested to be the main reason for malignant transformation in PA. The aim of this study was to determine the prevalence of BRCA1/2 mutations in PA and Ca-ex-PA.

Materials and Methods: A total of ninety salivary gland tumors (45 Ca ex-PA and 45 PA) were selected. Immunohistochemistry was performed for all samples. Analyses were conducted through SPSS software version 22.0 (SPSS, Inc., Chicago, IL, USA). Chi-square test was used to examine the differences between the variables. Significant level was set at 0.05.

Results: In general, 93.3% of PA samples showed positive staining for BRCA1 (in myoepithelial cells); however, BRCA2 positivity was found in 60% of samples (in myoepithelial cells). Among 45 samples of Ca-ex-PA, 93.3% of showed positivity for BRCA1 and 80% of samples showed positivity for BRCA2. Chi-square test found differences between PAs and Ca-ex-PAs regarding BRCA1/2 mutations in ductal cells and myoepithelial cells ( P = 0.007, 0.000), respectively.

Conclusions: The present study found a trend toward the presence of BRCA1/2 mutations in PA and Ca-ex-PA samples. Patients with BRCA1/2 mutation carriers are excellent cases for therapies, such as the poly (ADP) ribose polymerase inhibitor.