Analysis of Amplified Genes in Samples of Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma by CGH-Array Technique

Abstract Introduction Pleomorphic adenoma (PA) is a benign lesion of the salivary glands that can suffer malignant transformation to carcinoma ex adenoma pleomorphic (CXPA). The pathogenesis of CXPA has been attributed to the accumulation of genetic disorders in preexisting PAs. However, there is no confirmation whether there is a common target gene involved in all histopathological subtypes or the decisive factors for malignant transformation in a histopathological subtype are specific. Objectives To further analyze genes found in PA and CXPA using the CGH-array technique. The genes found were analyzed using the InteractiVenn virtual tool (http://www.interactivenn.net/) and grouped into a Microsoft Excel worksheet. Results: Of the 460 genes amplified in the studied samples, 287 (62.4%) were related only to CXPA, whereas 144 (31.3%) were related to residual PA. Twenty-nine (6.3%) of these genes were common between residual PA and CXPA. Regarding the degree of invasion of CXPA, there was an increase in the number of genes amplified as the degree of invasion and aggression increased: 8 genes related to intracapsular CXPA, 65 to minimally invasive CXPA, and 373 to weakly invasive. Moreover, when comparing residual AP and intracapsular CXPA, two genes were common to these groups: ERRB2 and GRB7. As for the histological subtype, the high-grade samples had more amplifications (320 amplified genes) than the low-grade ones (129 genes). Three of these genes were common among residual PAs and CXPA: HMGA2, RPSAP52, and LOC100129940. As for the replicates, MYNC, ERBB2, BRIP1, and HMGA2 were the most repeated amplified genes in the residual PAs. HMGA2, ERRBB2, CDK12, RPSAP52, LOC100129940, and LOC100507250 were the genes with the most replicates in CXPA. Conclusion HMGA2, ERRB2, and RPSAP52 may play a key role in PA carcinogenesis, whereas GRB7, CDK12, MYNC, and BRIP1 appear to act as coadjutants.