http://www.bioconductor.org/packages/release/bioc/vignettes/clusterProfiler/inst/doc/clusterProfiler.html  
brca <- scan("brca.txt",what="")
kirc<- scan("kirc.txt",what="")
prad <- scan("prad.txt",what="")
thca <- scan("thca.txt",what="")
ucec <- scan("ucec.txt",what="")

library("org.Hs.eg.db")
library(clusterProfiler)
db <- org.Hs.eg.db
entriz_brca <- select(db,brca,"ENTREZID","SYMBOL")
entriz_kirc <- select(db,kirc,"ENTREZID","SYMBOL")
entriz_prad <- select(db,prad,"ENTREZID","SYMBOL")
entriz_thca <- select(db,thca,"ENTREZID","SYMBOL")
entriz_ucec <- select(db,ucec,"ENTREZID","SYMBOL")

enrichGO_brca <- enrichGO(gene = na.omit(entriz_brca[,2]),  organism = "human", ont = "BP", pvalueCutoff = 0.05, readable= TRUE)
enrichGO_kirc <- enrichGO(gene = na.omit(entriz_kirc[,2]), organism = "human", ont = "BP", pvalueCutoff = 0.05, readable= TRUE)
enrichGO_prad <- enrichGO(gene = na.omit(entriz_prad[,2]), organism = "human", ont = "BP", pvalueCutoff = 0.05, readable= TRUE)
enrichGO_thca <- enrichGO(gene = na.omit(entriz_thca[,2]), organism = "human", ont = "BP", pvalueCutoff = 0.05, readable= TRUE)
enrichGO_ucec <- enrichGO(gene = na.omit(entriz_ucec[,2]), organism = "human", ont = "BP", pvalueCutoff = 0.05, readable= TRUE)
 
summary(enrichGO_brca)
 summary(enrichGO_kirc)
 summary(enrichGO_prad)
 summary(enrichGO_thca)
 summary(enrichGO_ucec)

mylist <- list(summary(enrichGO_brca)$ID,summary(enrichGO_kirc)$ID,summary(enrichGO_prad)$ID,summary(enrichGO_thca)$ID,summary(enrichGO_ucec)$ID)
intersect_GO <-  Reduce(intersect,mylist)