“…During the last few years, an increasing number of studies have reported that xenobiotic compounds from different sources are able to mimic the natural estrogens, thus exerting comparable effects by activating gene transcription through ERα and/or ERβ ( Effenberger et al , 2005 ; Escande et al , 2006 ; Gutendorf and Westendorf, 2001 ; Sonneveld et al , 2006 ; ter Veld et al , 2006 ; van der Woude et al , 2005 ). Estrogens stimulate cell proliferation in normal developing breast tissues and may prevent osteoporosis by increasing bone mineral density ( Douchi et al , 2007 ). However, several studies also suggest that estrogens may stimulate the growth of a large proportion of ERα-positive breast cancers ( Hartman et al , 2006 ; Lazennec, 2006 ; Monroe et al , 2005 ; Pedram et al , 2006 ; Weitzmann and Pacifici, 2006 ).…”