Bioinformatics analysis revealed that genes positively associated with SOX9 expression in thymomas were enriched in the extracellular matrix-receptor interaction pathway and the TGF-β signaling pathway, the latter of which plays important roles in regulating stromal cells and has potent immunosuppressive effects on both innate and adaptive immune cells in the tumor microenvironment (30). Here, SOX9 is linked to thymoma.