The expression characteristic and prognostic role of Siglec‐15 in lung adenocarcinoma

Abstract Sialic acid‐binding immunoglobulin‐like lectin‐15 (Siglec‐15) has been identified as an immune suppressor and a promising candidate for immunotherapy of cancer management. However, the association between Siglec‐15 expression and clinicopathological features of lung adenocarcinoma (LUAD), especially the prognostic role, is not fully elucidated. In this present study, a serial of bioinformatics analyses in both tissue and cell levels were conducted to provide an overview of Siglec‐15 expression. Real‐time quantitative PCR (qPCR) test, western blotting assay, and immunohistochemistry (IHC) analyses were conducted to evaluate the expression of Siglec‐15 in LUAD. Survival analysis and Kaplan–Meier curve were employed to describe the prognostic parameters of LUAD. The results of bioinformatics analyses demonstrated the up‐regulation of Siglec‐15 expression in LUAD. The data of qPCR, western blotting, and IHC analyses further proved that the expression of Siglec‐15 in LUAD tissues was significantly increased than that in noncancerous tissues. Moreover, the expression level of Siglec‐15 protein in LUAD was substantially associated with TNM stage. LUAD cases with up‐regulated Siglec‐15 expression, positive N status, and advance TNM stage suffered a critical unfavorable prognosis. In conclusion, Siglec‐15 could be identified as a novel prognostic biomarker in LUAD and targeting Siglec‐15 may provide a promising strategy for LUAD immunotherapy.