[{"from": "human", "value": "Provide a brief overview of this molecule. [C][O][C][=C][Branch1][#C][C][=C][C][=Branch1][Ring2][=C][Ring1][=Branch1][C][C][=Branch1][C][=O][O][O]"}, {"from": "gpt", "value": "The molecule is a monocarboxylic acid that is a catecholamine metabolite.  Homovanillic acid may be used a marker for metabolic stress, tobacco usage or the presence of a catecholamine secreting tumor, such as neuroblastoma or pheochromocytoma."}]