Different gene expression in the breast after pregnancy

1019 Background: The protective effect of an early first full-term pregnancy (FFTP) in relation to breast cancer risk is well known, but the molecular and cell-specific mechanisms involved remain unclear. Methods: We analysed the global gene expression profiles of normal mammary tissues taken from a matched multiparous and nulliparous woman using Serial analysis of Gene Expression (SAGE) and Generation of longer cDNA fragments from SAGE tags for Gene Identification. Results: The differentiation markers such as caseinκ, caseinβ, keratin14 en CCAAT/enhancer binding protein β and δ are increased after pregnancy. Genes like bullous pemphigoid antigen 1, decorin, vimentin, retinoid acid receptor responder, and the transcription factor early growth response 1 are also candidate markers for a pregnancy-induced differentiation. Histon deacetylase 2, Calpain, CAXII, collagen 1, osteonectin and connective tissue growth factor are decreased after pregnancy. Several of the genes that are lost after pregnancy encoded ...