Through this approach, gain-of-function mutations in genes encoding phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) and its related regulatory subunits have been identified to significantly enhance the anti-tumor capability of engineered CD8+ T cells ex vivo, which could potentially aid in guiding the engineering design of cell-based immunotherapy [243]. The gene discussed is CD8A; the disease is neoplasm.