Stromal reaction and prognosis in acinic cell carcinoma of the salivary gland

Abstract

Primary acinic cell carcinoma (ACC) is an uncommon malignant neoplasm of the salivary gland (SG), which usually presents as slow growing tumor. We reported a 69-year-old woman with tumor in the right parotid gland with a 5-year progress. Biopsy sections revealed a hybrid form of ACC with a low- and high-grade component and prominent lymphoid tissue in tumor stroma. Immunohistochemistry was performed to define the molecular profile of this unusual ACC, with special interest for stromal influence on to the proliferative activity of ACC with dedifferentiation. We detected that the level and the type of stromal lymphoid reaction (particularly CD8+/CD4+ ratio) had a significant influence on to Ki-67 index in the high-grade component of ACC, as well as the involvement of the CXCR4 signaling axis in the stromal reaction influence. We suggest that tumor stroma may be a source of potential new tumor biomarkers which can determine the aggressivity of this tumor.