A preliminary study of IgG4 expression and its prognostic significance in oral squamous cell carcinoma

Abstract Background IgG4, which plays a pivotal role in the progression of phenotypically diverse tumors, serves as a prognostic marker because of its influence on cancer immunity. Nevertheless, the functions of IgG4 in tongue squamous cell carcinoma (TSCC) remained to be identified. Methods To evaluate the significance of IgG4 expression in TSCC, we performed immunohistochemical analysis of patients with TSCC (n = 50) to evaluate the correlation of IgG4 expression with patients’ clinicopathological features and prognoses. Results Higher IgG4 expression detected in TSCC tissues was associated with the less advanced mode of invasion (Yamamoto-Kohama [YK] 1–3) (P = 0.031) and with well-differentiated TSCC (P = 0.077). Kaplan–Meier analyses revealed that the higher IgG4 expression group exhibited better prognosis indicated by overall survival (OS) (P = 0.04) and recurrence-free survival (RFS) (P = 0.016). Univariate analysis of OS indicated that IgG4 expression was associated with longer OS (P = 0.061), and multivariate analysis of RFS revealed that IgG4 expression served as an independent prognostic factor for longer RFS (P = 0.005). Conclusion These results indicate that relatively higher IgG4 levels serve as a favorable prognostic factor for TSCC.