Periostin expression in malignant lymphoma and Warthin's tumor

According to recent studies, periostin expression is significantly higher in cardiac disease and tumor tissues in the majority of cancers compared with normal tissues. Periostin was reported to be expressed in the stroma of Warthin's tumors. In the present study, we focused on the periostin expression in Warthin's tumor and malignant lymphomas, which require differentiation from these tumors. This study included 26 patients (28 specimens; 14 men and 12 women) with a mean age of 68.4 (range 51-85) years who underwent parotid tumor resection at the Division of Otorhinolaryngology, Tohoku Medical and Pharmaceutical University, between May 2016 and March 2022, and were clinically and pathologically diagnosed as Warthin's tumors and malignant lymphomas. Formalin-fixed, paraffin-embedded sections from the surgical specimens were immunostained with anti-periostin antibodies to evaluate the expression and distribution of periostin. Histologically, the tumors were diagnosed as Warthin's tumors in 13 cases (15 specimens) and malignant lymphomas in 13 cases (13 specimens). An increased expression of periostin was found in 24 (12 Warthin's tumors and 12 malignant lymphomas) of the 28 samples (85.7%) in the stroma of both Warthin's tumors and malignant lymphomas. Three distinct patterns of periostin expression were observed: negative, superficial, and infiltrative. Statistically significant differences were found between periostin expression patterns and the histological classification of the tumors. Our results suggest that periostin may be involved in the pathogenesis of Warthin's tumors and malignant lymphomas, potentially serving as a novel biomarker for these conditions.