[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C][=C][Branch1][=Branch1][N][=C][N][Ring1][Branch1][C][S][C][C][N][C][=Branch1][Ring1][=N][C][N][C][#N]"}, {"from": "gpt", "value": "The molecule is a histamine H(2)-receptor antagonist.  Enhancing anti-tumor cell-mediated responses, cimetidine blocks histamine's ability to stimulate suppressor T lymphocyte activity and to inhibit natural killer (NK) cell activity and interleukin-2 production.  Cimetidine also may inhibit tumor growth by suppressing histamine's growth-factor activity and blocking histamine-induced stimulation of vascular endothelial growth factor (VEGF), a pro-angiogenic growth factor. (NCI04)"}]