The structural and functional state of breast cancer tumor cells with different receptor status

Abstract

The structural and functional state of breast cancer tumor cells (TC) in groups of primary patients with different molecular subtypes of cancer was studied. In 75 primary patients with breast cancer, the receptor status of the tumor and the proliferative activity index Ki-67 were determined by the immunohistochemical method. Patients were divided into the following 6 groups: triple negative cancer, HER-2, RE, RE + RP, RE + HER-2 positive subtypes of cancer and three times positive cancer. Using standard methods of electron microscopy, the ultrastructure (US) of TC was investigated. It has been established that the US of the TC of the non-luminal breast cancer subtypes is predominantly characterized by large (possibly polyploid) undifferentiated forms with large, often pleiomorphic nuclei (PMN), whose function is growth and division, which corresponds to a high level of Ki-67, as well as a high incidence of PMN and phagosomes. For tumors with the expression of hormonal receptors, the most characteristic feature is the presence of intracellular lumens in the cytoplasm, which indicates a noticeable proteinsynthetic and secretory activity. RE-positive tumors have the lowest frequency of PMN and phagosomes, as well as the level of Ki-67, and a high frequency of intracellular lumens. In tumors of combined subtypes that do not have specific US signs, there is a mutual influence of hormonal receptors and HER-2 on the level of fission processes, the frequency of PMN and the ratio of nuclei of different sizes, obviously, due to the competition of hormonal receptors and HER-2 for targets that switch the functional activity of the cell or synthesis or division processes. Common to all the studied groups is the high heterogeneity of cell populations, in which, in addition to the characteristic for each of them, forms inherent in other subtypes are present. It has been established that each of the studied molecular subtypes has inherent characteristic US signs associated with the characteristics of their receptor status. A close correlation between the US indicators and proliferative activity was revealed. The heterogeneity of the TC population is observed in each of the studied cases. Co-expression of two to three receptors significantly modifies the studied parameters. The stages of the formation of intracellular gaps in the TC are illustrated. Keywords: breast cancer, ultrastructure, receptor subtypes.