PDCD1 and cancer: The network constructed from the ten upregulated genes indicated that the majority of changes were in pathways relating to immune responses, including cytotoxic T lymphocyte-mediated apoptosis (p = 1.44e-02), antigen presentation pathway (p = 1.65e-02), CTLA4 signaling in cytotoxic T lymphocytes (p = 3.79e-02), and PD-1 and PD-L1 cancer immunotherapy (p = 4.42e-02) (Fig. 6).