Objective: to estimate the expression of cell adhesion molecules E- and P-cadherin, as well as that of cadherin-catenin complexes in invasive lobular breast cancer (BC) cells. Material and methods. 250 cases of postoperative material from patients diagnosed with invasive lobular BC were studied. The expressions of cell adhesion molecules E-cadherin, P-cadherin, β-catenin, p120 catenin, and vimentin were determined by immunohistochemical assay in all cases. The examined cases were divided into molecular biological subtypes, based on the evaluation of estrogen receptors (ER), progesterone receptors (PR), HER-2/neu, and Ki-67 proliferative index. Results. The membrane expression of E-cadherin on the tumor cells was found to be preserved in 93%; the cytoplasmic expression of β-catenin and p120-catenin appeared in 60 and 72% of cases, respectively. The expression of P-cadherin was detected in 82% of cases. The coexpression of E- and P-cadherin was noted in 90% of all the examined cases. There was a correlation between the expression of E- and P-cadherins (V=0.34; p<0.05). Conclusion. The BC cells showed the coexpression of E- and P-cadherins, as well as release of the molecules β- and p120-catenins into the cytoplasm of tumor cells, which leads to the activation of intracellular mechanisms for changing the structure of the cytoskeleton and the level of proliferation. The above-mentioned mechanisms are accompanied by the activation of epithelial-mesenchymal transition. The intracellular mechanisms resulted in progressive cancer and its metastasis