CD4 and small cell lung carcinoma: In SCLC, the top 10 OX40/OX40L-related biological processes and pathways were also enriched in the activation, maturation, and proliferation of T cells, such as cytokine–cytokine receptor interaction, chemokine signaling pathway, NF-kappa B signaling pathway, etc. Positive correlation was found between the expression of OX40/OX40L and T-cell markers, such as CD3, CD4, and CD8 expression (17, 52–54).