I am running GSVA on normalized RNA seq data. Is it acceptable to get all negative enrichment scores for a pathway? The heatmap below shows GSVA scores with pathways in rows and samples in columns. We note that some rows are all blue (i.e., enrichment scores for all samples for that pathway are negative). For those blue pathways, distributions of enrichment scores are unimodal and approx. symmetric with mean < 0. Can this happen? Or is a pathway supposed to have both positive and negative enrichment scores? In the paper, it appears that kernels are calculated, accounting for other samples' expression level. I am not sure if the results can be trusted. Please help! Thanks!