Increased mucin 1 expression in recurrence and malignant transformation of salivary gland pleomorphic adenoma

Soares A B, Demasi A P D, Altemani A & de Araújo V C
(2011) Histopathology 58 , 377–382
Increased mucin 1 expression in recurrence and malignant transformation of salivary gland pleomorphic adenoma Aims: Pleomorphic adenoma (PA) is the most common salivary gland tumour with a tendency to recur (RPA) and a risk of malignant transformation. Mucin 1 (MUC‐1) plays a role in the progression of many tumours and may be a marker to predict RPA. The aim of this study was to evaluate MUC‐1 expression in different phases of the adenoma to carcinoma sequence. Methods and results: Twenty‐one cases of PA, 18 cases of RPA, three cases of RPA with focal transformation (TRPA) and 11 cases of carcinoma ex‐pleomorphic adenoma (CXPA) were analysed immunohistochemically for MUC1 expression using an antibody to MUC1/DF3. MUC1 reactivity in RPA was stronger than that observed in PA and, in all the different carcinoma groups, MUC‐1 expression was significantly higher in carcinoma than in RPA and PA. Conclusion: This study has confirmed that MUC‐1 is related to the recurrence of PA and that this molecule is associated with malignant transformation of PA with carcinoma cells overexpressing MUC‐1.