Histological Staining by Tritiated Actinomycin D: A Useful Tool to Study Neoplastic Cell Heterogeneity and Estrogen Sensitivity of Mammary Tumors

Abstract

The MXT mouse transplantable mammary cancer is characterized by significant amounts of steroid hormone receptors. This model, as other solid tumors, contains diverse subpopulations of neoplastic cells. In the present study this pattern was examined as well as the influence of exogenous physiologic doses of estradiol on tumor cell subpopulations. Their identification was undertaken at the morphological level employing incubation of tritiated actinomycin D with fixed material followed by autoradiography. This semiquantitative cytochemical method has proved itself to be a useful tool in order to assess the cellular heterogeneity of carcinoma cells.