MTOR and neoplasm: As a byproduct of glycolysis, lactate inhibits the PI3K/Akt/mTOR pathway, further suppressing glycolysis in CTLs.134 In vitro experiments have shown that lactate can inhibit the proliferation and cytokine production of human CTLs.135 Accumulation of lactate and the acidic environment of the TME are also found to reduce CTL infiltration.136 The knockdown of lactate dehydrogenase A (LDHA) in tumor cells, which reduces lactate production, has been successful in reversing the decrease in CTL infiltration.