Clinical Significance of Serum Type III Interferons in Patients with Gastric Cancer.

Type III interferon (IFN) is a newly established IFN that shows roles different from those of type I and II IFNs. However, the effect of type III IFN on the prognosis of patients with gastric cancer (GC) is controversial. This study aimed to investigate the effects of serum IFN-α, IFN-β, IFN-γ, IFN-λ1, and IFN-λ2/3 levels on the survival of patients with GC. LEGENDplex bead-based immunoassays were used to analyze the serum IFN-α, IFN-β, IFN-γ, IFN-λ1, and IFN-λ2/3 levels in patients with GC and healthy volunteers. Flow cytometry was used to test the IFN concentrations. Compared with the healthy controls, the patients with GC had significantly decreased serum IFN-α, IFN-γ, and IFN-λ1 levels, but significantly increased serum IFN-λ2/3 level. Analysis of the serum IFN concentrations and clinical parameters of the patients with GC showed significant correlations of serum IFN-α, IFN-β, IFN-γ, and IFN-λ2/3 levels with clinical stages. Serum IFN-λ1 levels significantly correlated with tumor location, histopathology, and lymph node involvement. Serum IFN-λ2/3 levels significantly correlated with lymph node involvement and distant metastasis. In addition, serum IFN-α, IFN-β, and IFN-γ levels significantly correlated with clinical stage and lymph node metastasis. Serum IFN-β and IFN-γ levels also significantly correlated with Lauren classification. Furthermore, the patients with stage IV GC exhibited significantly lower IFN-λ2/3 levels and higher IFN-α, IFN-β, and IFN-γ levels than the patients with stage I-III GC. The univariate analysis revealed that tumor sizes of >5 cm, higher clinical stage, and high IFN-λ2/3 level were significantly associated with poor prognosis. This study shows the relationship between serum IFN level and GC progression. High serum IFN-λ2/3 levels were associated with poor prognosis and could be a novel biomarker for evaluating GC progression and predicting the outcomes of nonmetastatic GC.