Cytochemistry of cell surface sialoglycoconjugates in endometrial adenocarcinoma. Effects of medroxyprogesterone therapy.

Ferritin- and rhodamine-conjugated Limulus polyphemus agglutinin was used to localize, by electron microscopy, and to quantify, by microfluorometry, the cell surface sialoglycoconjugates in human endometrial adenocarcinoma before and after medroxyprogesterone acetate therapy. In the untreated tumor the lectin labelling was irregularly distributed on the cell surface, with a maximum density at the apical area and at the intercellular border; high values of the density-binding sites on cell surface were also detected by cytofluorometry. The binding pattern in both electron microscopy and microfluorometry on normal tissue and on tumor tissue submitted to medroxyprogesterone acetate stimulation appeared clearly modified; the lectin labelling concerned the apical areas only (also after treatment with chelating agents), with low fluorometric values of the reactive site density. The differences found in the lectin binding to the cellular sialic acid residues may be due to sialoglycoconjugate quantitative changes and/or to their different reactivity resulting from alterations of the cell membrane architecture. The data appear also correlated with a different proliferative activity and ploidy level of the three situations analyzed.