Expression of Metabolism-Related Proteins in Lacrimal Gland Adenoid Cystic Carcinoma

OBJECTIVES: To investigate the expression and the clinical implications of metabolism-related proteins in lacrimal gland adenoid cystic carcinoma (ACC) in comparison with salivary gland ACC. METHODS: Human tissue samples of lacrimal gland ACC (n = 11) and salivary gland ACC (n = 64) were analyzed. Immunochemistry was used to measure expression of proteins related to glycolysis (glucose transporter 1, hexokinase II, carbonic anhydrase IX, and monocarboxylate transporter 4 [MCT4]), glutaminolysis (glutaminase 1 [GLS1], glutamate dehydrogenase [GDH], and amino acid transporter 2 [ASCT2]), mitochondria (adenosine triphosphate [ATP] synthase, succinate dehydrogenase A [SDHA], and succinate dehydrogenase B), and glycolytic intermediate metabolism (phosphoserine phosphatase [PSPH], serine hydroxymethyl transferase 1 [SHMT1]). RESULTS: GLS1 and ASCT2 were more highly expressed, and GDH, ATP synthase, and SDHA were expressed to a lesser degree in lacrimal gland ACC than in salivary gland ACC (P < .05). Lacrimal gland ACC showed less of a mitochondrial phenotype than did salivary gland ACC (P = .001). Positivity of MCT4 and PSPH was related to shorter disease-free survival, and SHMT1 was related to shorter overall survival (P < .05). CONCLUSIONS: Lacrimal gland ACC exhibited higher expression of GLS1 and ASCT2, compared with salivary gland ACC. Overexpression of MCT4, PSPH, and SHMT1 was associated with poorer prognosis.