The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP2112_r117960 http://rdf.wikipathways.org/Pathway/WP2112_r117960/DataNode/f0c53 (MAPK)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier