Toward a new approach in tumor cell heterogeneity studies using the concept of order.

A new methodology was developed to study dynamic processes topographically in biological systems by means of a graph-theoretical method. It is based upon order parameters obtained from a minimal spanning tree analysis coupled with computer simulations. The method was used to analyse the heterogeneous behavior of two neoplastic cell lines after treatment with laminin.

[Breast tissue: estrogen receptors. Immunohistochemical and biochemical analysis of normal and hyperplastic tissue and carcinoma in situ. Apropos of 86 cases].

Estrogen receptors (ER) were investigated using immunohistochemical techniques in 54 cases and biochemical techniques in 38 cases on a series of biopsy specimens of normal, hyperplasic and malignant mammary tissue (intraductal carcinoma). Immunohistochemical data were submitted to quantitative and semi-quantitative analysis (SAMBA 200, TITN). On normal tissue, immunostaining is bright and evenly distributed in galactophores and ductulo-lobular junctions; it is unevenly distributed but consistently present in lobules and increasing after menopause.

Estradiol membrane binding sites on human breast cancer cell lines. Use of a fluorescent estradiol conjugate to demonstrate plasma membrane binding systems.

A fluorescent estradiol macromolecular complex was used to study and to characterize steroid binding to membranes of living target cells. Ligand binding to plasma membranes was quantitated with a sensitivity of 0.1 nM.

Early alterations at the plasma membrane of breast cancer cell lines in response to estradiol and hydroxytamoxifen.

The time course of the early stage of estradiol-17 beta (E2) and hydroxytamoxifen (OHTAM) action at the plasma membrane of hormone-responsive MCF-7 and non-responsive MDA-MB-231 (MDA) breast cancer cell lines was investigated using scanning electron microscopy (SEM), electron probe X-ray microanalysis and microelectrophysiology analysis. SEM showed a marked increase in the density and the length of microvilli (MV) on MCF-7 cells treated with 1 nM estradiol for 1 min. This membrane response disappeared at 5 min.