IGFBP5 and breast carcinoma: Recent evidence shows that 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a typical organic pollutant, exerts toxic effects on human breast carcinoma cells and endometrial carcinoma cells by activating IGFBP5 (Tanaka et al., 2007), indicating that IGFBP5 may act as an endogenous regulatory factor involved in tissue damage induced by environmental factors.