Prognostic significance of Myb protein and its downstream target genes in lacrimal gland adenoid cystic carcinoma

OBJECTIVES: Lacrimal gland adenoid cystic carcinoma (ACC) is a rare and lethal malignancy associated with a poor prognosis, with no known therapeutic targets. The clinical relevance of Myb, Sox4, c-Kit protein expression, and the MYB::NFIB fusion gene in lacrimal gland ACC is not well known. The current study aims to investigate the prognostic significance of Myb, Sox-4, c-Kit protein, and the MYB::NFIB fusion gene in lacrimal gland ACC. METHODS: A total of 30 histopathologically diagnosed lacrimal gland ACC cases were included in this study. Myb, Sox4, c-Kit expression, and MYB::NFIB gene fusion were evaluated by immunohistochemistry and fluorescence in situ hybridization, respectively. The results were correlated with clinicopathologic features and patient survival. RESULTS: Immunoexpression of Myb, Sox4, and c-Kit was observed in 70%, 63%, and 63% of ACC cases, respectively. Myb expression showed a significant association with the solid and cribriform histologic patterns, Sox-4 expression, and disease-free survival. On univariate analysis, Myb expression, solid histologic pattern, bone erosion, intracranial extension, and advanced tumor stage were indicators of poor prognosis. c-Kit expression showed a significant association with advanced tumor stage. MYB::NFIB fusion, detected in 47% of cases, was significantly associated with intracranial extension. CONCLUSIONS: Myb protein emerged as a prognostic indicator in the pathogenesis and clinical outcomes of patients with lacrimal gland ACC.