CD8A and neoplasm: This possibility was also raised in studies of pancreatic ductal adenocarcinoma (PDAC), in which the activation of CD8+ T cells along with down-regulation of MDSCs and up-regulation of M1 macrophage differentiation and T helper 1 (Th1) differentiation of CD4+ T cells, as documented by elevated expression of T-box transcription factor 21 (TBX21, also known as T-Bet), TNF-α, and IFN-γ, was favored by bacterial ablation, resulting in alleviation of PDAC tumor burden [54].