Discovery proteomics reveals potential protein signature associated with malignant phenotype acquisition in pleomorphic adenoma.

Objective: To analyze the proteomic profile of salivary pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA) samples and correlate them with the malignant transformation of the PA. Materials and methods: Thirty samples (10 PA, 16 CXPA, and 4 residual PA) were microdissected and submitted to liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The proteomic data and protein identification were analyzed through LC‐MS/MS spectra using the MaxQuant software. Results: The proteomic analysis identified and quantified a total of 240 proteins in which 135 were found in PA, residual PA, and CXPA. The shared proteins were divided into six subgroups, and the proteins that showed statistically significant differences (p > 0.05) and fold‐change > or <2.5 in one subgroup to another subgroup were included. Seven proteins (Apolipoprotein A‐I—APOA1, haptoglobin—HP, protein of the synaptonemal complex 1—SYCP1, anion transport protein of band 3—SLC4A1, subunit μ1 of AP‐1 complex—AP1M1, beta subunit of hemoglobin—HBB, and dermcidin—DCD) were classified as potential protein signatures, being HP, AP1M1, and HBB with higher abundance for PA to residual PA, APOA1 with higher abundance for PA to CXPA, SLC4A1 with lower abundance in the PA to CXPA, SYCP1with lower abundance for residual PA to CXPA, and DCD with higher abundance in the CXPA with epithelial differentiation to myoepithelial differentiation. Conclusions: In this work, we demonstrated the comparative proteomic profiling of PA, residual PA, and CXPA, and seven were proposed as protein signatures, some of which may be associated with the malignant phenotype acquisition. [ABSTRACT FROM AUTHOR]