Features of CD44+/CD24-low phenotypic cell distribution in relation to predictive markers and molecular subtypes of invasive ductal carcinoma of the breast.

Breast cancer is the most widespread pathology among women. Despite the current progresses in research and treatment of metastatic breast cancer, mortality caused by this disease is still high, because above mentioned therapy is limited due to existence of cells resistant to therapy . Cancer stem cells are the only cells with ability of unlimited proliferative activity and cancerous potential, thus, they participate in the growth, progression and dissemination of cancer. Cancer stem cells are resistant to various forms of therapy, including chemotherapy and radiotherapy . Results of examination showed that 50% of all cases are positive on so called markers of stem cells, thus 45% of cases are negative. CD44+/CD24-low cases (cases that reveal stem cell-phenotype) in the group of invasive ductal carcinoma of Luminal A molecular subtype are almost as many as CD44+/CD24+ and CD44-/CD24+ phenotype cancers. In this group non-stem phenotype cases are 65%, so 5 times more than stem cell phenotype cancers. 1324 postoperative breast materials studied through 2008-2012 at the laboratory of "Pathgeo-Union of Pathologists" LTD and Academician N. Kipshidze Central University Clinic were used as test materials and specimens from 393 patients with invasive ductal carcinoma were selected. CD44/CD24 markers' expression in phenotypically different cancers and clinic-pathologic parameters as well as various biological features was conducted by the Pearson's correlation analysis and using X2 test. Statistical analysis of obtained numeral data was held using SPSS V.19.0 program. Confidence interval of 95% was considered statistically significant. Stem cell phenotype positive cases are with the highest percentage represented in Luminal B and basal-like molecular subgroup that to our minds is associated with their aggressive behavior and resistance to chemotherapy. Relatively good prognosis and response to chemotherapy of Luminal A molecular subtype cancers are to be stipulated by lower percentage of cases with stem cells phenotype. With regard to the dimension of cancer the analysis of stem cell phenotype cancers showed that frequency of stem cell phenotype (CD44+/CD24-low) dramatically increases from T1 to T4 cancers. High density of stem cell phenotype cancers in cancers with metastatic lymphatic nodes proves that presence of mentioned phenotype plays a role in progression and dissemination. On the one hand, little amount of stem cells phenotype cancers (CD44+/CD24-low), on the other hand absence of negative cases for markers of stem cell in Her2 subtype makes us consider that come phenotype, close to stem-cell phenotype, plays the leading role in Her2 positive cases.