Latent forms of transforming growth factor-beta 2 (TGF-beta(2)) in breast cyst fluid

Transforming growth factor-beta (TGF-beta) is secreted by cells in high mol ecular weight, latent forms and the in vivo mechanisms for the activation r emain largely an enigma. Women who have palpable breast cyst with intracyst ic Na/K < 3 may have a higher risk of developing breast cancer than those w ith intracystic Na/K > 3. Finding of significantly higher concentrations of TGF-beta(2) in the Na/K > 3 group than Na/K < 3 group may explain the lowe r risk of breast cancer in the Na/K > 3 group. The aim of the present study was to characterise the latent forms of TGF-beta(2) in breast cyst fluid u sing HPLC, affinity chromatography, SDS-PAGE and immunostaining techniques. We found that TGF-beta(2) is present in high molecular weight, latent form s in breast cyst fluid: as a complex probably with alpha 2-macroglobulin an d a 56 kD protein which is likely to be a precursor form of TGF-beta(2).