Videomicrofluorometry of progesterone receptors and their genes in breast cancer cells

Expression of progesterone receptors (PR) at the cell level is heterogeneous. Quantification by image analysis of several fluorescent immunostainings (PR, Ki-67 antigen, DNA) on breast cancer cell lines shows that this heterogeneity is partially linked to cell proliferation kinetic. Simultaneous detection of chromosome 11 (on which PR gene is located) by in situ hybridization and PR immunostaining do not demonstrate any relationship between the number of chromosome 11 and PR cell positivity, probably because numbers of chromosome 11 and of PR gene copies are not correlated, as shown by a double fluorescent in situ hybridization on metaphases.