The Separation Of Breast Cancer Stem Cells And Study On Related Drug-resistance Proteins

Objective:To separate breast cancer stem cells from primary human breast cancer tissue, then observe the morphological characteristics of cancer stem cells and differentiated cells; analyze the relation between the proportion of breast cancer stem cells and clinical pathological parameters; explore the expression of ER, PR, HER2, P-gp, GST-π, LRP and Topo Ⅱ in breast cancer stem cellsMethods:30fresh specimens of breast invasive ductal carcinoma were made into single cell suspensions by mechanical separation, then breast cancer stem cells (CD44+CD24-/low cells) and differentiated cells (CD24+and CD44-CD24-cells) were separated from them by immunomagnetic sorting. Immunocytochemical technique was employed to detect the expression of ER, PR, HER2, P-gp, GST-π, LRP and Topo Ⅱ in two groups.Results:(1) Under optical microscope, there were no significant differences of morphology between breast cancer stem cells and differentiated cells.(2) The proportion of CD44+CD24-/low in breast cancer was about0.24%～9.70%, an average of2.96%.(3) No significant relationship was found between the proportion of breast cancer stem cells and clinical pathological parameters such as age, tumor size, lymph node metastasis and histological grade.(4) There were significant differences between breast cancer stem cells and differentiated cells in the expression of ER, PR and HER2(P<0.05). The phenotype was different too (P<0.05). ER-, PR-and HER2-was the predominant phenotype in breast cancer stem cells, accounting for about66.7%; however, ER and/or PR+, HER2-was the predominant phenotype in differentiated cells, accounting for about43.3%.(5)The P-gp positive rate in breast cancer stem cell was73.3%, while in differentiated cells it was40.0%, there was a statistically significant difference between the two groups, P<0.05. The Topo Ⅱ positive rate in breast cancer stem cell was40.0%, while in differentiated cells it was76.7%, there was a statistically significant difference between the two groups, P<0.05. The GST-π positive rate in breast cancer stem cell was23.3%, in differentiated cells it was13.3%, there was no significant difference between the two groups, P>0.05. The expression of LRP positive rate in breast cancer stem cell was13.3%, in differentiated cells it was13.3%, there was no significant difference between the two groups, P>0.05.Conclusion:(1) The proportion of breast cancer stem cells in breast cancer is about2.96%; there are no significant differences of morphology between breast cancer stem cells and differentiated cells under optical microscope.(2)The expression of ER, PR and HER2in breast cancer stem cells could be either positive or negative, yet the majority of them are negative; ER-, PR-and HER2-is the predominant phenotype in breast cancer stem cells, which maybe relate to the failure of endocrine therapy.(3) Compared to differentiated cells, breast cancer stem cells can increase their drug resistance by enhancing the expression of P-gp and decreasing the expression of Topo Ⅱ, which maybe play important roles in the failure of chemotherapy in breast cancer.