Most solid malignancies comprise not only tumor cells but also fibroblasts, vascular endothelial cells, extracellular matrix, many types of immune cells that exert both immunosuppressive functions [e.g., tumor-associated macrophages, myeloid-derived suppressor cells (MDSCs), and regulatory T-cells] and tumor-fighting functions (e.g., cytotoxic CD8+ T-cells, CD4+ Th1, natural killer cells), as well as multiple extracellular soluble molecules (e.g., cytokines, growth factors, chemotactic factors). The gene discussed is CD4; the disease is neoplasm.