The following DataNodes have no identifier: 1
http://classic.wikipathways.org/instance/WP2892_r117537 http://rdf.wikipathways.org/Pathway/WP2892_r117537/DataNode/e060d (PIK3)
More details at https://www.wikipathways.org/WikiPathwaysCurator/DataNodesTests/dataNodesWithoutIdentifier