Transforming growth factor beta (
TGF-beta) is a multifunctional regulator of cellular growth and differentiation in many cell types and has a growth inhibitory effect on mammary epithelial cells. The
TGF-beta 2
isoform has been shown to be present in high concentrations in
breast cyst fluid and might have a protective role in
breast cancer. In addition, oestrogens play an important role in
breast cancer development, and
oestrone sulphate (E1S) might be the main source of active oestrogens in the breast. The aim of this study was to assess the effect of
TGF-beta 2 on oestrogen synthesis in an attempt to understand the mechanism by which
TGF-beta 2 may exert a protective effect in
breast cancer. In this study, higher concentrations of
TGF-beta 2 significantly inhibited the conversion of E1S to oestrone (E1) and the conversion of E1 to the potent oestrogen,
oestradiol (E2).
TGF-beta 2 did not have any effect on MCF-7 cell growth or on E2 to E1 conversion. In conclusion,
TGF-beta 2 might exert a protective role in
breast cancer by reducing the amount of active oestrogens present in the breast.