Reactome License Agreement
Creative Commons Attribution 3.0 Unported License
Reactome is a free and open-source project, and you are free to download Reactome software and data. The contents of Reactome are copyright (c) 2003-2010 Cold Spring Harbor Laboratory (CSHL), Ontario Institute for Cancer Research (OICR) and the European Bioinformatics Institute (EBI). The software and information contents are distributed under the terms of the Creative Commons Attribution 3.0 Unported License, which grants parties the non-exclusive right to use, distribute and create derivative works based on Reactome, provided that the software and information is correctly attributed to CSHL, OICR and EBI.
More details about the Creative Commons License is available here