Alpha-2-macroglobulin in tear fluid: a step in diagnosis of lacrimal gland tumors

The purpose of the work was to study the activity of the acute phase inflammation protein alpha-2-macroglobulin (α2-MG) in the tear fluid (TF) of patients with different morphological variants of lacrimal gland tumors (LGT). Material and methods. The study included 33 patients with morphologically verified diagnosis of LGT. The control group (healthy individuals) was additionally recruited for comparative evaluation. TF was collected from both eyes before surgery using filter paper. The activity of α2-MG was determined by enzymatic method. Results. It was revealed that in epithelial tumors of the LG — pleomorphic adenoma and lacrimal gland carcinoma, there was an increase of α2-MG activity in the TF on the side of the lesion compared to the control group. At the same time, in 67 % (n = 4) of LG carcinoma cases there was a tendency to increase α2-MG activity also on the healthy side. In LG lymphomas, no significant differences from the norm in α2-MG activity in the TF both on the tumor side and on the healthy side could be detected. The α2-MG activity did not depend on the tumor volume and clinical features. In patients with LG carcinoma with a history of more than 10 months, high values of α2-MG activity in the TF on the contralateral healthy side were detected. Conclusion. For the first time we evaluated the activity of α2-MG protein in the TF and showed characteristic features in different morphologic variants of LGT. The search for biochemical markers in TF opens new opportunities for studying the pathogenesis of this category tumors, which may contribute to the development of personalized therapy. The obtained data allow to improve diagnostics of LGT and can be applied in clinical practice in the system of complex diagnostics at the stage of preoperative preparation.