A common approach in analyzing gene expression profiles was identifying differential expressed genes that are deemed interesting. The enrichment analysis we demonstrated in Disease enrichment analysis vignette were based on these differential expressed genes. This approach will find genes where the difference is large, but it will not detect a situation where the difference is small, but evidenced in coordinated way in a set of related genes. Gene Set Enrichment Analysis (GSEA)1 directly addresses this limitation. All genes can be used in GSEA; GSEA aggregates the per gene statistics across genes within a gene set, therefore making it possible to detect situations where all genes in a predefined set change in a small but coordinated way. Since it is likely that many relevant phenotypic differences are manifested by small but consistent changes in a set of genes.
Genes are ranked based on their phenotypes. Given a priori defined set of gens S (e.g., genes shareing the same DO category), the goal of GSEA is to determine whether the members of S are randomly distributed throughout the ranked gene list (L) or primarily found at the top or bottom.
There are three key elements of the GSEA method:
We implemented GSEA algorithm proposed by Subramanian1. Alexey Sergushichev implemented an algorithm for fast GSEA analysis in the fgsea2 package.
In DOSE3, user can use GSEA algorithm implemented in DOSE
or fgsea
by specifying the parameter by="DOSE"
or by="fgsea"
. By default, DOSE use fgsea
since it is much more fast.
Leading edge analysis reports Tags
to indicate the percentage of genes contributing to the enrichment score, List
to indicate where in the list the enrichment score is attained and Signal
for enrichment signal strength.
It would also be very interesting to get the core enriched genes that contribute to the enrichment.
DOSE supports leading edge analysis and report core enriched genes in GSEA analysis.
gseDO
fuctionIn the following example, in order to speedup the compilation of this document, only gene sets with size above 120 were tested and only 100 permutations were performed.
library(DOSE)
data(geneList)
y <- gseDO(geneList,
nPerm = 100,
minGSSize = 120,
pvalueCutoff = 0.2,
pAdjustMethod = "BH",
verbose = FALSE)
head(y, 3)
## ID Description setSize
## DOID:0060041 DOID:0060041 autism spectrum disorder 165
## DOID:12849 DOID:12849 autistic disorder 165
## DOID:0060040 DOID:0060040 pervasive developmental disorder 175
## enrichmentScore NES pvalue p.adjust qvalues rank
## DOID:0060041 -0.3880133 -1.542078 0.01449275 0.07945344 0.03462604 2308
## DOID:12849 -0.3880133 -1.542078 0.01449275 0.07945344 0.03462604 2308
## DOID:0060040 -0.3909104 -1.545017 0.01515152 0.07945344 0.03462604 2308
## leading_edge
## DOID:0060041 tags=29%, list=18%, signal=24%
## DOID:12849 tags=29%, list=18%, signal=24%
## DOID:0060040 tags=30%, list=18%, signal=25%
## core_enrichment
## DOID:0060041 1760/9732/7337/5175/6532/54806/6326/1499/7157/221037/627/2571/3082/3791/27347/596/22829/23426/324/5021/4885/7248/8604/4208/26470/64221/9037/3952/93664/2944/7102/2550/4915/4922/26960/1746/2697/6863/2891/367/4128/7166/6505/18/9370/57502/79083
## DOID:12849 1760/9732/7337/5175/6532/54806/6326/1499/7157/221037/627/2571/3082/3791/27347/596/22829/23426/324/5021/4885/7248/8604/4208/26470/64221/9037/3952/93664/2944/7102/2550/4915/4922/26960/1746/2697/6863/2891/367/4128/7166/6505/18/9370/57502/79083
## DOID:0060040 1760/9732/7337/5175/6532/54806/6326/1499/7157/221037/627/3399/2571/3082/3791/27347/596/22829/23426/324/5021/4885/7248/8604/3397/4208/3400/26470/64221/9037/3952/93664/2944/7102/2550/4915/4922/26960/1746/2697/6863/2891/367/4128/7166/6505/5348/18/9370/57502/79083
gseNCG
fuctionncg <- gseNCG(geneList,
nPerm = 100,
minGSSize = 120,
pvalueCutoff = 0.2,
pAdjustMethod = "BH",
verbose = FALSE)
ncg <- setReadable(ncg, 'org.Hs.eg.db')
head(ncg, 3)
## ID Description setSize enrichmentScore NES pvalue
## lung lung lung 173 -0.3880662 -1.629393 0.01492537
## breast breast breast 133 -0.4869070 -1.958353 0.01538462
## lymphoma lymphoma lymphoma 188 0.2999589 1.294687 0.08823529
## p.adjust qvalues rank leading_edge
## lung 0.04615385 0.03238866 2775 tags=31%, list=22%, signal=25%
## breast 0.04615385 0.03238866 2930 tags=33%, list=23%, signal=26%
## lymphoma 0.17647059 0.12383901 2087 tags=21%, list=17%, signal=18%
## core_enrichment
## lung SETD2/ATXN3L/LRP1B/BRD3/ARID1A/INHBA/RB1/ADCY1/LYRM9/NF1/CTNNB1/TP53/SATB2/STK11/CTIF/CTNNA3/KDR/COL11A1/FLT3/APC/ADGRL3/FGFR3/NCAM2/DIP2C/APLNR/SLIT2/EPHA3/RUNX1T1/ZMYND10/ZFHX4/GLI3/TNN/PLSCR4/DACH1/ERBB4
## breast KMT2A/ERBB3/SETD2/ARID1A/GPS2/NCOR1/RB1/MAP2K4/NF1/TP53/PIK3R1/STK11/CDKN1B/PTGFR/APC/CCND1/TRAF5/MAP3K1/ESR1/TBX3/FOXA1/GATA3
## lymphoma DUSP2/EZH2/PRDM1/MYC/ZWILCH/IKZF3/PLCG2/IDH2/HIST1H1C/MAGEC3/CD79B/ETV6/HIST1H1E/HIST1H1B/IRF8/CD28/SLC29A2/DUSP9/TNFAIP3/DNMT3A/SYK/TNF/BCR/HIST1H1D/DSC3/UBE2A/PABPC1
gseDGN
fuctiondgn <- gseDGN(geneList,
nPerm = 100,
minGSSize = 120,
pvalueCutoff = 0.2,
pAdjustMethod = "BH",
verbose = FALSE)
dgn <- setReadable(dgn, 'org.Hs.eg.db')
head(dgn, 3)
## ID Description setSize enrichmentScore
## umls:C0032914 umls:C0032914 Pre-Eclampsia 334 -0.3066475
## umls:C0338656 umls:C0338656 Impaired cognition 342 -0.3266625
## umls:C0004936 umls:C0004936 Mental disorders 348 -0.3087838
## NES pvalue p.adjust qvalues rank
## umls:C0032914 -1.313172 0.01190476 0.105042 0.06511376 1909
## umls:C0338656 -1.400314 0.01190476 0.105042 0.06511376 1997
## umls:C0004936 -1.322042 0.01204819 0.105042 0.06511376 2007
## leading_edge
## umls:C0032914 tags=29%, list=15%, signal=25%
## umls:C0338656 tags=23%, list=16%, signal=20%
## umls:C0004936 tags=20%, list=16%, signal=17%
## core_enrichment
## umls:C0032914 PLAC1/PSG5/ERCC2/ADD1/ACTG2/PECAM1/PGF/VEGFC/DDAH2/F7/PDE5A/ADAM12/CAPN10/LTF/SOD3/COL4A6/TEK/IL5/PRCP/HPGD/SCNN1A/MBL2/CYP1A1/IL1R1/INSR/PROC/HP/VWF/HDC/EFNA1/FABP2/MMP3/NPR1/OXTR/LPA/EDIL3/MGP/APLNR/PYGM/SELP/FGF1/GJA4/FGF14/MMP13/SLC22A5/COL1A2/ANG/COL1A1/LEPR/PROS1/FGF2/PPARG/CRHBP/SYNPO/COL3A1/LPL/THBD/MMP10/COL5A2/LEP/PTGER3/MMP2/PDGFC/GSTM1/CFH/NOV/ESR1/IGF1R/TPBG/HSPA1L/HSPG2/VCAN/COL5A1/SPARC/NR3C2/CLU/ENPP1/F13A1/HTRA1/F3/AGTR1/GSTT1/PLAT/AR/IRS1/IL6ST/COL4A5/THBS4/IGF1/ELN/ADIPOQ/CORIN/HLA-DQA1/FABP4/CX3CR1
## umls:C0338656 NR3C1/CAPN3/SLC2A10/CREBBP/ZNF224/ITM2B/ELK3/CLN5/GAD1/BACE1/HGF/SERPINA3/MBL2/SST/EGR1/INSR/UTRN/ARL4D/PVALB/EEF1A2/DYM/CD36/RAB40AL/RBMS3/TREM2/PER3/OXTR/TSC1/CDR1/IGFALS/TPPP/SELP/NGF/BCHE/KCNS3/APBB2/TRPM4/RUNX1T1/MME/ABCB1/PPARG/MVP/NME8/SPG11/LPL/SLC26A4/FHL5/KL/LEP/FTO/NAIP/SORL1/ESR1/ABCC8/CST3/LAMA2/HHAT/LRP1/CLU/ALB/SPON1/NTS/HTRA1/GSTT1/GRIA2/MAGI2/IRS1/TAT/COL4A5/AASS/IGF1/ITPR1/BMP4/LRP2/MAPT/ERBB4/GRP
## umls:C0004936 BDNF/BCL9/NR3C1/PCLO/DEAF1/FZD4/CREBBP/ITIH3/GLI1/GAD1/GRM5/CUL3/NUCB2/CHRM2/WFS1/PROC/HTR1A/PRKG1/HPGDS/DBH/MMP3/APC/FZD10/OXTR/NDN/PTPRN2/TPPP/SGCE/NGF/LEPR/ABCB1/CRHBP/SHH/MAGEL2/GLT8D1/LEP/FTO/PER2/ATXN1/CADPS2/NRXN3/CTNND2/XBP1/TCF4/ESR1/NTF3/HSPG2/CACNA1C/GABBR1/MAGI1/NR3C2/NTRK2/ANOS1/APOD/TAC1/ZBTB20/GRIA2/UCN/MAOA/CARTPT/TPH1/SLC1A1/CACNA1D/MAOB/ADH1B/NLGN4X/ERBB4/GRP
1. Subramanian, A. et al. Gene set enrichment analysis: A knowledge-based approach for interpreting genome-wide expression profiles. Proceedings of the National Academy of Sciences of the United States of America 102, 15545–15550 (2005).
2. S., A. An algorithm for fast preranked gene set enrichment analysis using cumulative statistic calculation. biorxiv doi:10.1101/060012
3. Yu, G., Wang, L.-G., Yan, G.-R. & He, Q.-Y. DOSE: An r/bioconductor package for disease ontology semantic and enrichment analysis. Bioinformatics 31, 608–609 (2015).