I am interested in a pathway of Reactome, because I would like to use it for a GSEA, however in the Broad Institute the gene set is not in the C2 subcategory of Reactome.
I could only find a reference for this pathway from last July as having "New pathway Illustrations" in the mailing list archive. Also the reactome.db package of Bioconductor doesn't seem to contain it, even if it was updated this April.
How can I know if a pathway is new or not? How can I obtain the gene set of the pathway R-HSA-2559583 ?