Background Pleomorphic adenoma (PA) is the most common salivary gland tumour. Although classified as benign, it has a tendency to recur (recurrent pleomorphic adenomas (RPA)), as well as the ability to undergo malignant transformation. It has been suggested that mutations in various families of growth factors and growth factor receptions are involved in the autonomous growth of tumour cells. The aim of the present study was to investigate the participation of platelet-derived growth factor (PDGF)-A, PDGF-B, PDGF-Rα, fibroblast growth factor (FGF)-2, Flg and BEK in PA, RPA and recurrent pleomorphic adenoma with malignant transformation (TRPA).

Methods 18 cases of PA, 16 cases of RPA and two cases of RPA with focal malignant transformation (TRPA) were analysed for growth factor expression utilising immunohistochemical techniques via tissue microarray.

Results There was a significant difference in PDGF-A, PDGF-B, PDGF-Rα, FGF-2, Flg and BEK expression in all groups. When comparing non-recurrent with recurrent tumours, PDGF-A, PDGF-B, PDGF-Rα, FGF-2, Flg and BEK reactivity in RPA was stronger than that observed in PA. All proteins were highly expressed in TRPA.

Conclusions This research suggests that PDGF-A, PDGF-B, PDGF-Rα, FGF-2, BEK and Flg can be related to the recurrence of PA. In addition, this study shows that TRPA cells overexpress all growth factors, which has been reported in association with the malignant transformation.