| Breast cancer which have a great impact on women's lives and health is a common malignancy of women. The incidence of breast cancer is the first two malignancies in many cities of China.Cancer stem cells which are of stem cell properties such as self-replacement are a small number of cells within the tumor cells. The formation of cancer stem cells is generally considered as normal stem cells stimulated by various internal and external factors that come into effect. Some tumor stem cells may be due to multiple gene mutations and abnormal self-renewal process occurring in nonnal stem cells.The stem cell growth regulation disorders appeared and stop at some stage of differentiation leading unlimited proliferation. Cancer stem cells determine tumor biological characteristics and prognosis of patients.Recently, breast cancer stem cell research has made significant progress.Breast cancer is the cancer stem cell-related disease has been widely recognized.Although different histological forms, clinical presentation, biological characteristics of breast cancer patients vary, they are all associated with a significant relationship between breast cancer stem cells. In 2003, for the first time, Al-Hajj isolated CD44+/CD24-/low cancer cell lines from human primary breast cancer and metastatic breast cancer pleural effusions by using transplant NOD/SCID mouse mammary fat pad testing methods and flow cytometry analysis. They have differentiation potential and have the ability as self-renew. They showed evidences that only one hundred cells with this phenotype were able to form tumors in nude mice, whereas tens of thousands of tumou cells with other phenotypes may not able to form tumors. Breast cancer stem cells in solid tumors was identified.Oct4 which is also known as POU5F1 or Oct3, often express in totipotent embryonic cells and has a specific role in the early stages of embryo. Oct4 gene belongs to transcription factors family of Pou area. Oct4 expresses in the primordial germ cells, mouse preimplantation embryos, oocytes, gastrula ectoderm and embryonic stem cells, but can not express in differentiated cells. It means that Oct4 and cell pluripotency differentiation are closely connected. Oct4 may be a key gene for specific differentiation of pluripotent. It marks the totipotent differentiation of cells. Therefore, cells with the expression of Oct4 gene can be considered as potential of pluripotent stem cells, these cells may be the tumor starting cells.Sox2 gene belongs to sox (SRY-related HMG box) family, all the sox family members contain a highly conserved HMG box DNA binding domain. Sox2 which specifically bind HMG domain of target genes, plays an essential role in maintaining pluripotency of stem cells. Sox2 can influence cell fate and embryonic development, which regulates neural stem cells, embryonic stem cell self-renewal and differentiation processes.Al-Hajj has separated the CD44+/CD24-/low cancer cell, which have the potentiality of differentiation and can do self-renewal. This kind of cells can not only generate cells of other kinds but can perform self-replication as well. Fillmore CM has found that several CD44+/CD24-/low cells in the breast carcinoma cell system have similar characteristics of stem cells such as drug-resistance, multidirectional differentiation and self-renewal. CD44+/CD24-/low cells as the marker of the breast carcinoma stem cells have been widely acceptedThe genotyping of the breast carcinoma is a new way which classifies breast cancer on the specific expression of genes.This new way of classification is more accurate than traditional ways (which mainly decide on the size of the tumor, histological type and the status of lymphatic metastasis) in predicting the risk of the recurrence and the metastasis of breast carcinoma, in analyzing the treatment effect and in assessing the survival prognosis of the patient. Breast cancer has been classified into 5 genotypings as Luminal A,Luminal B,HER-2 over-express,Basal-like and Normal-like, each with different clinical manifestation, prognosis and treatment. Study suggested that the sensibility of Luminal A and Luminal B types to chemotherapy is comparatively low, the sensibility of the HER-2 over-express patients are comparatively high.while the Basal-like type are the most sensitive to chemotherapy before operation. In prognostic comparison among the 5 mentioned above, Luminal A and Normal-like is the best, Luminal B is better, HER-2 over-express type is worse and Basal-like type is the worst. What are the inverse proportion of breast cancer stem cell among the genotypings of breast cancers?How different are the expression level of the stem cell markers? Are the differences in the biological behavior of different breast cancer genotypings closely related to the different contents of its tumor stem cells?These problems are rarely studied within our country and abroad. Therefore the experiment performed here was mainly for the purpose of observing the expression and the significance, in various genotypings of breast cancer, of the tumor stem cell marker Sox2, Oct4 protein and the breast cancer stem cell of the CD44+/CD24-/low marker in order to make a preliminary investigation on the biological behavior of each genotyping of breast cancer from the standpoint of tumor stem cell.Methods:As for our methedology the immunohistochemical staining method is adopted to detect 120 samples of Sox2, Oct4 in invasive intraductal carcinoma of breast. Meanwhile the immunohistochemical double staining methed is adopted to test the expression of CD44+/CD24-/low breast cancer cells.We discuss the expression and mutual relationship of Sox2 and Oct4 in every genotyping of breast cancer,and also conduct statistical analysis on their possible correlation.On basis of HER-2,ER,PR conditions of breast cancer tissue from different patients,we design all the 120 samples into 4 parts:Luminal A,45 cases (37.5%); Luminal B,29 cases (24.2%); HER-2 over expression,27 cases(22.5%).Triple negative breast cancer,19 cases (15.8%)Results:1 CK5/6 expression are generally located in the cytoplasm. The positive signal is brown. CK5/6 antibody immunohistochemistry in Triple negative breast cancer breast carcinoma can determine whether this type is from the basal cells. In this study, a total of 19 samples showed (ER-, PR-, HER-2-) phenotype and the CK5/6 staining was positive, in line with Basal-like carcinoma of the breast diagnostic criteria.2 Oct4 protein expresses in nucleus of the tumor cells and the positive signal is brown. Positive cells were distributed densely punctate and sometimes were distributed diffusely. The positive rate of Oct4 of each genotyping of breast cancer is as follows:Luminal A (31.1%),Luminal B (34.5%),HER-2 overexpression (66.7%),Basal-like (89.5%) (χ2=27.668, P<0.001). The positive rate of stem cell marker Oct4 protein in Basal-like breast tumor tissue genotype was significantly higher than the other three genotypes. The positive rate of stem cell marker Oct4 protein in Luminal A breast cancer was the lowest.3 Sox2 protein expresses in nucleus of the tumor cells and the positive signal is brown. Positive cells were distributed densely punctate and sometimes were distributed diffusely. The positive rate of Sox2 of each genotyping of breast cancer is as follows:Luminal A (13.3%),Luminal B (62.1%),HER-2 overexpression (81.5%),Basal-like (84.2%) (χ2=50.737, P<0.001). The positive rate of stem cell marker Sox2 protein in Basal-like breast tumor tissue genotype was significantly higher than the other three genotypes. The positive rate of stem cell marker Sox2 protein in Luminal A breast cancer was the lowest.4 In 120 cases of breast cancer, from the Luminal A, Luminal B, HER-2 over-expression to the Basal-like type the expression of Oct4 and Sox2 is an upward trend. The result shows that the expession of Sox2 and Oct4 in breast cancer tissue are positively correlated with high significance(r=0.506;P<0.001). 5 CD44 protein expresses in membrane or cytoplasm of the tumor cells. The positive signal is red. CD24 protein expresses in membrane or cytoplasm of the tumor cells.The positive signal is tan. In 120 cases of breast cancer,the positive rate of CD44+/CD24-/low cell of each genotyping of breast cancer is as follows:Luminal A (64.4%),Luminal B(65.5%),HER-2 overexpression(55.6%),Basal-like(73.7%) (χ2=1.644;P=0.65>0.05).We can see that there is no relationship between the amount of CD44+/CD24-/low cell and breast cancer genotypings (χ2=1.644, P=0.65) (P>0.05)6 Oct4 and the age of the breast cancer are correlated with high significance (χ2=16.59,P<0.001).Oct4 and the size of the tumor are correlated with high significance (χ2=12.006, P<0.001).There is no relationship between the expression of Oct4 and the lymph node metastasis of the breast cancer (χ2=0.001, P=0.975) (P >0.05)7 Sox2 and the age of the breast cancer are correlated with high significance (χ2=24.848, P<0.001). Sox2 and the size of the tumor are correlated with high significance (χ2=17.614, P<0.001).There is no relationship between the expression of Sox2 and the lymph node metastasis of the breast cancer (χ2=0.083, P=0.773) (P >0.05)8 There is no relationship between the expression of CD44+/CD24-/low cell and the age of the breast cancer(x2=2.415, P=0.120) (P>0.05).There is no relationship between the expression of CD44+/CD24-/low cell and the size of the tumor (χ2=0.946, P=0.331) (P>0.05).There is no relationship between the expression of CD44+/CD24-/low cell and the lymph node metastasis of the breast cancer (χ2=1.029, P=0.310) (P>0.05)Conclusions:1 High malignant genotypes of breast cancer have more tumor cells with the characteristics of stem cells. Differences of the number of cancer stem cells led to differences in clinical manifestations and prognosis of genotypes of breast cancer.2 The expession of Sox2 and Oct4 in breast cancer tissue are positively correlated suggesting possible synergies between Oct4 and Sox2. Oct4 and Sox2 co-regulate network of stem cells to maintain self-renewal and multi-differentiation ability of embryonic stem cells.3 There is no relationship between the amount of CD44+/CD24-/low cell and breast cancer genotypings.4 Oct4,Sox2 and CD44+/CD24-/low cell may be from different subset of breast cancer stem cells. The subset of Oct4 and Sox2 is correlated with the genotyping of breast cancer.The subset of CD44+/CD24-/low is not correlated with the genotyping of breast cancer... |
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