Gene Fusions in Differential Diagnosis of Salivary Gland Neoplasms: A Systematic Review.

Salivary gland tumors represent a  rare and morphologically heterogeneous group of neoplasms, which represents a  significant diagnostic challenge for histopathologists. Diagnosis is based primarily on morphological evaluation, but immunohistochemical methods are often a necessary complementary tool. However, due to immunophenotype overlap between different tumor entities, even immunohistochemistry may not always allow an unambiguous diagnosis. In recent years, characteristic genomic alterations, particularly gene fusions, have been identified in a number of salivary gland tumors. These alterations are tightly tumor type specific, and their detection may be crucial in diagnostically difficult cases. In addition, selected genetic changes may have prognostic and/ or potential therapeutic significance in the era of personalized medicine. The aim of this review article is to summarize current knowledge in this area.