Ontology of Biological Attributes id OBA_2056864 (level of proto-oncogene tyrosine-protein kinase receptor Ret (human) in cerebrospinal fluid) is the amount of a proto-oncogene tyrosine-protein kinase receptor Ret (human) when measured in cerebrospinal fluid. Also known as: cerebrospinal fluid proto-oncogene tyrosine-protein kinase receptor Ret (human) amount.