Biological pathways in ConsensusPathDB are represented as sets of interactions, whose compositions are adopted from the source databases. This means that individual interactions rather than entire pathways from different databases are compared with each other. This was necessary because the concept of pathway is defined very differently in the respective source databases and the pathway boundaries are rather unclear. For example, KEGG's Glycolysis/gluconeogenesis pathway contains 31 reactions whereas Reactome's Glycolysis contains 10 reactions.
