Peculiarities and prognostic significance of epithelial-mesenchymal transition in secondary edematous breast cancers

Background. Secondary edematous breast cancers (SEBC) do not possess distinct morphological or molecular characteristics, yet they are marked by more aggressive biological behavior compared to non-edematous forms. The issue of identifying morphological and molecular-biological criteria for SEBC that determine the clinical behavior of tumors remains unresolved. Purpose – was to investigate the peculiarities and prognostic significance of epithelialmesenchymal transition in SEBC. Materials and methods. Two study groups were formed: Group I – SEBC (30 cases) and Group II – 15 patients with locally advanced non-edematous breast cancer at stages T3-4N1-3M0. The parameters studied included: expression of pancytokeratin, cytokeratin 18 (CK18), E-cadherin, vimentin, N-cadherin, and the stage of epithelialmesenchymal transition (EMT). Results. In SEBC, all cases showed a positive reaction of cancer cells to pancytokeratin, while a heterogeneous reaction to CK18 was observed, which was statistically significantly lower in SEBC compared to the control group. A decrease in E-cadherin expression in SEBC was also demonstrated (p < 0.05), with 46.6% of cases showing a negative reaction, which was accompanied by the appearance of N-cadherin expression in 50% of SEBC cases. A negative correlation between N-cadherin and E-cadherin expression was identified (r = -0.46, p < 0.03). The prognostic significance of E-cadherin expression was also established. It was shown that metastatic SEBCs are characterized by reduced E-cadherin expression (χ² = 8.8, p < 0.05). Aberrant vimentin expression in the cytoplasm of cancer cells was found in 43.3% of SEBC cases. Based on the co-expression of epithelial phenotype markers (CK18 and E-cadherin) and mesenchymal phenotype markers (vimentin and N-cadherin), SEBC cases were classified according to EMT stage. EMT was absent in 36.6% of SEBC cases. No statistically significant association was found between the presence of EMT and the group affiliation of breast cancer (χ² = 0.4, p = 0.51). However, SEBC was characterized by a higher EMT stage. EMT stages 0–1 were observed in 46.6% of SEBC cases versus 93.3% in nonedematous breast cancer (χ² = 8.6, p < 0.01). Conclusions. SEBC is characterized by heterogeneous expression of cytokeratin 18, with significantly lower levels compared to the control group. A decrease in E-cadherin expression was also established (p < 0.05), which has prognostic value: metastatic SEBC cases showed a more pronounced decrease in E-cadherin levels (χ² = 8.8; p < 0.05). No correlation was found between the presence of EMT and breast cancer group affiliation (χ² = 0.4; p = 0.51), although SEBC demonstrated a higher EMT stage.