PCDH17/ROBO1 protein level ratio in blood (OBA_2055162, an Ontology of Biological Attributes term) can be described as follows. A compound attribute that is the ratio of amount of protocadherin-17 (human) in blood to amount of roundabout homolog 1 (human) in blood. Also known as: the ratio of amount of protocadherin-17 (human) in blood to amount of roundabout homolog 1 (human) in blood.