CD8A and neoplasm: GABA(B) receptor activated by tumor-derived GABA inhibits GSK-3β activity, enhances β-catenin signaling, and leads to stimulation of tumor cell proliferation and suppression of CD8(+) T cell intratumoral infiltration, suggesting its distinct role of being targeted pharmacologically to reverse immunosuppression beyond its traditional function as a neurotransmitter (135).