SLC6A8 and neoplasm: In support of this, tumor-infiltrating lymphocytes (TILs) upregulate the expression of creatine transporters, such as SLC6A8, facilitating the uptake of creatine and increasing the energy availability required for immune cell function.438 Numerous dietary therapies have been safely employed for various diseases.439 However, the influence of barriers and concentration gradients of the TME on the efficacy of these interventions remains poorly understood.