CD274 and neoplasm: Additionally, cancer-associated fibroblasts (CAFs) play an important role in the progression of OSCC cells by promoting tumor growth and modulating the immune response.160, 161, 162, 163 In particular, CAFs enhance the progression of OSCC by secreting cytokine IL-33, which binds to its receptor suppression of tumorigenicity 2 (ST2), thereby enhancing PD-L1 synthesis and expression.164