CTLA4 and neoplasm: T-cells responses have been observed against NSCLC tumor-associated antigens (TAA) (e.g., MAGE-A1, PRAME, MUC1) in NSCLC cell lines [13], which may result in activation of inhibitory immune checkpoint pathways/molecules such as programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), in what are known as markers for exhausted T cells [12].