The differentially expressed proteins between normal and tamoxifen-induced autophagic MCF-7 cells were studied by 2-DE combining with mass spectrometric analysis.Totally,there were 668±99 and 550±97 protein spots detected in the 2-DE maps from normal and autophagic MCF-7 cells respectively,among which 5 changed protein spots were identified by the Q-TOF MS/MS and database search.