Proteomic definition of normal human luminal and myoepithelial breast cells purified from reduction mammoplasties

Normal human luminal and myoepithelial breast cells separately purified fro m a set of 10 reduction mammoplasties by using a double antibody magnetic a ffinity cell sorting and Dynabead immunomagnetic technique were used in two -dimensional gel proteome studies. A total of 43,302 proteins were detected across the 20 samples, and a master image for each cell type comprising a total of 1,738 unique proteins was derived. Differential analysis identifie d 170 proteins that were elevated 2-fold or more between the two breast cel l types, and 51 of these were annotated by tandem mass spectrometry, Muscle -specific enzyme isoforms and contractile intermediate filaments including tropomyosin and smooth muscle (SM22) alpha protein were detected in the myo epithelial cells, and a large number of cytokeratin subclasses and isoforms characteristic of luminal cells were detected in this cell type, A further 134 nondifferentially regulated proteins were also annotated from the two breast cell types, making this the most extensive study to date of the prot ein expression map of the normal human breast and the basis for future stud ies of purified breast cancer cells.