Prognostic value of tumor–stroma ratio in oral carcinoma: Role of cancer‐associated fibroblasts

Abstract Objective Tumor‐stroma ratio (TSR) is a promising parameter representing the abundance of the stroma which has been validated in many solid tumors. However, it is still not clear which part of stroma mainly contribute to the prognostic value of TSR. The aim of this study is to confirm the prognostic value of TSR in a large cohort of oral squamous cell carcinoma (OSCC) and further demonstrated that cancer‐associated fibroblasts (CAFs)‐stroma ratio (CSR) contributed to the prognostic value of TSR. Materials and methods TSR was evaluated on hematoxylin and eosin stained tissue samples from 581 patients with OSCC, which divides patients into high (>50%) and low (<50%) stroma. Then, CSR was estimated on immunohistochemical staining slides of 100 patients selected from 581 patients. Results In multivariate analysis, TSR was identified as an independent prognostic factor for disease‐free survival (DFS) ( p < 0.001) and oral cancer‐specific survival (OCSS) ( p < 0.001). The interaction term reached statistical significance for histological grade for DFS and OCSS separately. Furthermore, the high‐stroma group had a higher CSR than the low‐stroma group. Conclusion The prognostic value of TSR is validated in OSCC particularly in moderate and high differentiation, and CSR plays its part in the prognosis of TSR.