Expression of LAG3 on tumor-infiltrating lymphocytes in salivary gland carcinomas

Introduction Salivary glad carcinomas (SGC) are rare head and neck malignancies. LAG3 belongs to the immune-checkpoint receptor proteins and can be found on the cell surface of cytotoxic and regulatory T cells. It controls T cell activation, response and growth. The expression of LAG3 and tumor infiltrate in SGC as well as the correlation to clinical and pathological characteristics was investigated. In addition, the prognostic significance of LAG3 expression in SGC was evaluated.

Methods Our study investigated the expression of LAG3 in SGC on a test (n = 33) and a validation cohort (n = 106). First, the histopathological diagnosis was validated using FISH and immunohistochemistry. The samples were then stained with anti-LAG3 IgG, CD8 and TP53 monoclonal antibodies. Clinical data including follow-ups of all patients were collected.

Results In this study, LAG3 expression was found on tumor-infiltrating lymphocytes in one third of the SGCs. The highest expression was found on salivary duct carcinoma (66.7 %) and adenocarcinoma NOS (ANOS). In addition, expression of LAG3 significantly correlated with advanced nodal metastasis, increased infiltration of cytotoxic T-cells and increased TP53 mutations. Especially in adenoid cystic carcinomas the expression of LAG3 was associated with a shorter event-free-survival.

Conclusion LAG3 is particularly found in aggressive entities and advanced tumors. The prognosis also seems to correlate with LAG3 expression in individual entities. The blockade of LAG3 could be used as a potential target for new and effective systemic immune therapies as an additional or palliative therapy option for these patients.

Poster-PDF A-1751.PDF

Publikationsverlauf

Artikel online veröffentlicht:
10. Juni 2020