Summary of the effect of immortalization on the gene expression of mouse embryonic fibroblasts as determined by gene expression microarray analysisa.

aThe expression level of genes in the untreated immortalizaed (passage 32) MEF was divided by levels in the untreated primary (passage 4) MEF to obtain fold changes.bImmortalization significantly affected the expression of these probes/genes. Multiple probes may be used to quantify the expression of the same gene. The number in the parenthesis represents the number of genes affected.cp value shown is Benjamini.