Background
Transforming growth factor‐β (TGF‐β) exerts its versatile function (oncogenic or tumor suppressive role) during the carcinogenesis in tumor microenvironment‐dependent manner. Considering the tumor heterogeneity, spatial and temporal distribution of TGF‐β in oral squamous cell carcinoma (OSCC) remained to be elucidated.
Methods
Formalin‐fixed, paraffin‐embedded sections derived from 73 patients with OSCC were immunostained, revealing expression patterns of TGF‐β, both at the regions of tumor center (TC) and invasive tumor front (ITF).
Results
The TGF‐β levels on tumor cells, fibroblast‐like cells (FLCs), and tumor‐infiltrating lymphocytes (TILs) were comparable and showed to be cell‐type‐independent manner. Although TC regions harbored less positive staining of TGF‐β than ITF in tumor cells (TGF‐βTumor cell) (89.0% vs 98.3%; P = 0.037), FLCs (TGF‐βFLC) (86.3% vs 96.6%; P = 0.043), and TILs (TGF‐βTIL) (83.6% vs 94.8%; P = 0.044), respectively, TGF‐β at TC regions, not at ITF, correlated to poor clinical outcomes. At TC regions, patients with high TGF‐βTumor cell had high recurrence rate, and patients with high TGF‐βTIL showed inferior worst pattern of invasion. Of note, high TGF‐βTumor cell at TC predicted shorter overall survival time, recurrence‐free survival, and disease‐free survival in patients with OSCC, whereas high TGF‐βTIL had no association with survival time. Cox regression analyses indicated that tumor cell‐derived TGF‐β at TC was an independent risk factor for survival outcome in patients with OSCC.
Conclusions
Tumor cell‐derived TGF‐β at TC regions, but not at ITF, could be a promising predictor for disease recurrence and poor prognosis of patients with OSCC.