[Proliferation and liberation kinetics of the tissue polypeptide antigen of MCF-7 cells. Hormonal influence]

The presence or absence of tissular polypeptide antigen (TPA) in the culture medium of hormone dependent breast cancer tumoral cells, the relationship between TPA concentration and cellular proliferative activity, have been investigated as well as whether TPA levels change in response to steroid preparations or the action of different antiestrogens. Results show that in MCF-7 cell line culture media, proteins antigenically related to TPA can be detected in concentrations which parallel the number of cells in culture. Consequently, TPA can be considered a cell proliferation marker. Hydroxy-tamoxifen at a concentration of 10(-7) M inhibited both cell proliferation and TPA antigen release, while the relative proportion between number of cells (valued by DNA quantification) and TPA concentration remained unchanged.