Dear Bioconductors, Now my problem is as follows: First of all, I read the microarray .gpr files to RGlist, then normalized it to MAlist. After that I convert the MAlist to exprSet for further analysis. Now, I want to filter genes in exprSet according to the names or probeID, but I found there is no geneNames Slot for my exprSet. How to find or keep the geneNames or ID for each genes? And how to filter by gene names? my partial code is like follows: rg<-read.maimages(...) ma.p<-normalizeWithinArrays(rg) ma.paq<-normalizeBetweenArrays(ma.p) exp<-as(ma.paq, "exprSet") > geneNames(exp) NULL ???? Or other approaches or suggestions? Thanks Regards, Yanju