Differentially expressed genes were investigated in mouse mammary gland epithelial cell line EpH4 using cDNA microarrays. In this preliminary study differences were found in gene expression
between cells growing on plastic substrate and in collagen gel. Eighty-three genes were shown to
be up-regulated and 49 down-regulated. Up-regulated expression of estrogen receptor, CREB, and
cyclin D1 genes suggest that they may be important for milk duct development.