The Pathway Commons  ontology contains data on pathways from multiple sources. Pathways include biochemical reactions, complex assembly, transport and catalysis events, and physical interactions involving proteins, DNA, RNA, small molecules and complexes.
Statistics can now be found in the footers of each table in the GREAT web output.
All ontology data was downloaded and built between Oct 14, 2011 and Feb 18, 2012.
GREAT v1.8 Pathway Commons statistics are available here.
GREAT v1.2 Pathway Commons statistics are available here.
Cerami, E.G., Bader, G.D., Gross, B.E., Sander, C. cPath: open source software for collecting, storing, and querying biological pathways, BMC Bioinformatics. 2006 Nov 13; 7:497.