The reason for this is the well-documented fact that tumor-infiltrating CD8+ T cells play an essential role during the anti-tumor response, and that they have been shown to correlate with an improved prognosis for tumor entities such as non-small cell lung cancer (NSCLC) [65], colorectal cancer [66], ovarian cancer [67] and melanoma [68]. The gene discussed is CD8A; the disease is neoplasm.