It has been shown that TGF-β can increase mitochondrial membrane potential (a measure of mitochondrial activity) in T cells and that CD8+CD103+ tumor-specific T cells have increased spare respiratory capacity; however, the connection to oxidative phosphorylation and/or fatty acid metabolism is unclear and may also be dependent on T cell differentiation status (97–100). This evidence concerns the gene TGFB1 and neoplasm.