It is known that particularities of microenvironment of a malignant tumor can influence its invasion and progress. Although BCSC is commonly believed to have a favourable prognosis, variants of aggressive disease course have been encountered lately. The task of this paper is comparative characteristics of factors of the local immunity in microenvironment of BCSC with various proliferation and under varied age particularities of patients. A number of distinctions according to content of local immunity factors in BCSC patients have been determined. Higher levels of proinflammatory cytokines, mostly IL-1 and IL-8, are shown in the tumor as compared to intact tissue; there is also a higher quantity of CD3+CD4+ and a lower quantity of CD3+CD8+ in the peritumoral area as compared to healthy tissue, with the tumor tissue containing more B-cells. Some differences have been found related to the proliferation of BCSC as well as to the age of the patients.