Hi Annabelle,
Our apologies, your messages were initially caught in the google groups spam filter seemingly for no particular reason.
To clarify; your ranking metric is the sign of the logFC*-log10(pValue), yes?
And with this ranking metric, your data only has positive enrichment results, and you looked in the separate report sections for each phenotype (pos and neg)?
Would you mind posting the enrichment plot from one of the sets that you did obtain a result from? I might help in assessing any dataset distributional issues that could be giving rise to this issue.
It can just simply happen sometimes though if there aren't sets in your analysis that are a good fit for the genes that are down-regulated, but it's pretty rare to see nothing at all. Any additional information you can provide us about the experimental design or GSEA configuration would be helpful.
-Anthony
Anthony S. Castanza, PhD
Curator, Molecular Signatures Database
Mesirov Lab, Department of Medicine
University of California, San Dieg