Research On The Expression Of ERβ In Breast Cancer Tissues And The Relationship Between ERβ And MMP2、MMP9、MFN2、KLF4

Objective: Breast cancer is one of the usual malignant tumors whichthreaten the health of women serilusly. In recent years, the incidence of breastcancer becomes higher and higher and the victims of breast cancer tend to beyoung. Thus, doctors attach much attention to the mechanisim and treatmentof breast cancer. Breast cancer is one of the estrogen-related diseases which iscaused by the interaction between estrogen and estrogen receptor. Twosubtypes of estrogen receptors play an important role in breast cancer, one isER α, the other is ER β. ER α was discovered firstly as the only one estrogenreceptor witch had been explored tens of years before. Since ER β has beenknown in1996, people began to focus on it and learned more about it.However, there isn’t any definite conclusion of the biological action of ER βin breast cancer. Some people draw a conclusion that the overexpression ofgene of ER β could lead to the occurence of tumors, while some people thinkthat the expression of ER β could inhibit the development of cancers andprotect the normal tissues. The gene of ER β acts as a transcription factorwhich regulates the transcription of target gene, however, there hasn’t beenenough reports on the ER β-related genes. Consequntly, in order to explore thetranscription mechanism of gene-ER β, we analyzed the secquences ofpromoter by PubMed database and discovered that the complementary basesequences of the promoters of MMP2、MMP9、MFN2and KLF4consistedwith the base sequences of gene-ER β. Thus, we speculated that the gene ofER β might regulate the transcription of the four genes. Our study is to detectthe expression of gene-ER β in breast cancer tissues and normal breast tissuesin the level of mRNA and protein respectively and analyze the relationbetween the expression of ER β gene and clinical pathological indexes. Furthermore, explore the connection between ER β and MMP2、MMP9、MFN2、KLF4by Western blot and RT-PCR with the purpose of providingthe basis for pathogenesis and treatment in breast cancer.Methods: Western blot and RT-PCR were used to detect the expression ofgene-ER β in breast cancer tissues and normal tissues in the mRNA level andprotein level, and then analyzed the association of the expression betweengene-ER β and clinical pathological indicators such as ages, menses, tumorsizes, clinical stages, histology grades, pathological types, the states of theaxillary lymph nodes. Moreover, Western blot and RT-PCR are also used toexplore the relevance of the expression between ER β gene and MMP2、MMP9、MFN2、KLF4in the level of mRNA and protein.Results:1The expression of ER β gene in breast cancer and normal breast tissues1.1The expression of ER β mRNAThe possitive rates of the expression of ER β mRNA in breast cancertissues and normal breast tissues were70.70%(28/40) and97.50%(39/40)respectively, there was a obvious difference between the two groups throughstatistical analysis (χ~2=11.114；P=0.001<0.05), and the possitive rate of ER βmRNA in breast cancer tissues was lower than the one in normal breasttissues.1.2The expression of ER β proteinThe possitive rates of the expression of ER β protein in breast cancertissues and normal breast tissues were69.46%(27/40) and92.50%(37/40)respectively, there was a obvious difference between the two groups throughstatistical analysis (χ~2=7.812；P=0.005<0.05), and the possitive rate of ER βprotein in breast cancer tissues was lower than the one in normal breasttissues.2The relationship between the expression of gene-ER β and clinicalpathological indicators2.1The relationship between the expression of ER β mRNA and clinicalpathological indicators 2.1.1Ages of patients. In the group of50years or below sufferers, the ER βmRNA expressed positively in nine of them, and7sufferers’ ER β mRNAwere negative. In the group of more than50years sufferers,19sufferers’ ER βmRNA were positive and5sufferers’ ER β mRNA were negative, there was noobvious difference in the distribution of ages through statistical analysis(χ~2=1.434；P=0.231＞0.05).2.1.2The menstrual conditions of the patients. In the group of pre-menopausepatients,11patients’ ER β mRNA were positive and6patients’ ER β mRNAwere negative. In the post-menopause patients,17patients’ ER β mRNA werepositive and6patients’ ER β mRNA were negative, there was no obviousdifference in the distribution of menstrual conditions through statisticalanalysis (χ~2=0.395；P=0.530＞0.05).2.1.3The tumor sizes of the patients. In the group of bump diameters≤2cm,12patients’ ER β mRNA were positive and6patients’ ER β mRNA were negative;in the group of bump diameter2-5cm,15patients’ ER β mRNA were positiveand5patients’ ER β mRNA were negative; in the group of bumpdiameter≥5cm,1patients’ ER β mRNA was positive and1patients’ ER βmRNA was negative. There was no obvious difference in the distribution oftumor sizes of the patients through statistical analysis (χ~2=0.173；P=0.677＞0.05).2.1.4The histological grades of the patients. In the group of grade I,8sufferers’ mRNA were positive and1patient’ s ER β mRNA was negative, inthe group of histological grade II,14sufferers’ ER β mRNA were positive and9patients’ ER β mRNA were negative, in the group of histological grade III,6sufferers’ ER β mRNA were positive and2patients’ ER β mRNA werenegative there was no obvious difference in the distribution of histologicalgrades of the patients through statistical analysis (χ~2=0.983；P=0.321＞0.05).2.1.5The TNM stages of the patients. In the group of stage I,8patients’ ER βmRNA were positive and5patients’ ER β mRNA were negative, in thegroup of stage II,15patients’ ER β mRNA were positive and6patients’ ER βmRNA were negative,in the group of stage III,5patients’ ER β mRNA were positive and1patient’s ER β mRNA was negative, there was no obviousdifference in the distribution of clinical stages though statistical analysis(χ~2=0.195；P=0.658>0.05).2.1.6The metastatic states of the axillary lymph nodes of the patients. In thegroup of negative axillary lymph nodes,14patients’ ER β mRNA werepositive and9patients’ ER β mRNA were negative, in the group of positiveaxillary lymph nodes,14patients’ ER β mRNA were positive and3patients’ER β mRNA were negative, there was no obvious difference in the distributionof metastatic states of the axillary lymph nodes through statistical analysis(χ~2=2.148；P=0.143＞0.05).2.1.7The pathological types of the patients. In the group of invasive ductalcarcinoma,22patients’ ER β mRNA were positive and11patients’ ER βmRNA were negative, in the group of other types,6patients’ ER β mRNAwere positive and1patients’ ER β mRNA were negative, there was no obviousdifference in the distribution of pathological types of the axillary lymph nodesthough statistical analysis (χ~2=0.297；P=0.586＞0.05).2.2The relationship between the expression of ER β protein and clinicalpathological indicators2.2.1Ages of patients. In the group of age≤50years, the ER β proteinexpressed positively in nine of them, and7sufferers’ ER β protein werenegative. In the group of more than50years,18sufferers’ ER β protein werepositive and6sufferers’ ER β protein were negative, there was no obviousdifference in the distribution of ages through statistical analysis (χ~2=1.538；P=0.215＞0.05).2.2.2The menstrual conditions of the patients. In the group of pre-menopausepatients,10patients’ ER β protein were positive and7patients’ ER β proteinwere negative. In the post-menopause patients,17patients’ ER β protein werepositive and6patients’ ER β protein were negative, there was no obviousdifference in the distribution of menstrual conditions through statisticalanalysis(χ~2=1.015；P=0.314＞0.05).2.2.3The tumor sizes of the patients. In the group of bump diameters≤2cm,12 patients’ ER β protein were positive and6patients’ ER β protein were negative;in the group of bump diameter2-5cm,14patients’ ER β protein were positiveand6patients’ ER β protein were negative; in the group of bumpdiameter≥5cm,1patients’ ER β protein was positive and1patients’ ER βprotein was negative. There was no obvious difference in the distribution oftumor sizes of the patients through statistical analysis (χ~2=0.010；P=0.919＞0.05).2.2.4The histological grades of the patients. In the group of grade I,7sufferers’ protein were positive and2patient’s ER β protein was negative, inthe group of histological grade II,14sufferers’ ER β protein were positive and9patients’ ER β protein were negative, in the group of histological grade III,6sufferers’ ER β protein were positive and2patients’ ER β protein werenegative there was no obvious difference in the distribution of histologicalgrades of the patients through statistical analysis (χ~2=0.118；P=0.731＞0.05).2.2.5The TNM stages of the patients. In the group of stage I,8patients’ ER βprotein were positive and5patients’ ER β protein were negative; in thegroup of stage II,14patients’ ER β protein were positive and7patients’ ER βprotein were negative; in the group of stage III,5patients’ ER β protein werepositive and1patients’ ER β protein was negative, there was no obviousdifference in the distribution of clinical stages through statistical analysis(χ~2=0.039；P=0.843＞0.05).2.2.6The metastatic states of the axillary lymph nodes of the patients. In thegroup of negative axillary lymph nodes,14patients’ ER β protein werepositive and9patients’ ERβ protein were negative, in the group of positiveaxillary lymph nodes,13patients’ ER β protein were positive and4patients’ER β protein were negative, there was no obvious difference in the distributionof metastatic states of the axillary lymph nodes through statistical analysis(χ~2=1.085；P=0.298＞0.05).2.2.7The pathological types of the patients.In the group of invasive ductalcarcinoma,21patients’ ER β protein were positive and12patients’ ER βprotein were negative, in the group of other types,6patients’ ER β protein were positive and1patients’ ER β protein were negative, there was no obviousdifference in the distribution of pathological types through statistical analysis(χ~2=0.474；P=0.491＞0.05).3The connection of the expression between ER β and MMP2、MMP9、MFN2、KLF4in breast cancer tissues3.1The relationship of mRNA between ER β and MMP2、MMP9、MFN2、KLF4in breast cancer tissues3.1.1ER β mRNA and MMP2mRNAThere was no statistical significance of linear relationship between ER βmRNA and MMP2mRNA through statistical analysis (P=0.207>0.05).3.1.2ER β mRNA and MMP9mRNAThere was no statistical significance of linear relationship between ER βmRNA and MMP9mRNA through statistical analysis (P=0.498>0.05).3.1.3ER β mRNA and MFN2mRNAThere were statistical differences of linear relationship between ER βmRNA and MFN2mRNA through statistical analysis(r=0.492；P=0.009<0.05),and they changed with the same trend.3.1.4ER β mRNA and KLF4mRNAThere was no statistical significance of linear relationship between ER βmRNA and KLF4mRNA through statistical analysis (P=0.689>0.05).3.2The relationship of protein between ER β and MMP2、MMP9、MFN2、KLF4in breast cancer tissues3.1.1ER β protein and MMP2proteinThere was no statistical significance of linear relationship between ER βprotein and MMP2protein through statistical analysis (P=0.300>0.05).3.1.2ER β protein and MMP9proteinThere was no statistical significance of linear relationship between ER βprotein and MMP9protein through statistical analysis (P=0.695>0.05).3.1.3ER β protein and MFN2proteinThere were statistical differences of linear relationship between ER βprotein and MFN2protein through statistical analysis(r=0.561; P=0.002<0.05), and the expression of MFN2protein and ER β protein changed with the sametrend.3.1.4ER β protein and KLF4proteinThere was no statistical significance of linear relationship between ER βprotein and KLF4protein through statistical analysis (P=0.218>0.05).Conclusion:1In both mRNA level and protein level, the positive rate of expression of ERβ gene in breast cancer tissues is lower than in the normal breast tissues. Thedecline or loss of ER β may induce the proliferation of breast tissue cells anddevelopment of cancer.2The expression of ER β don’t associate with the clinical pathologicalindicators such as ages, menses, tumor sizes, clinical stages, histology grades,pathological types, the states of the axillary lymph nodes in either the mRNAlevel or the protein level.3In both mRNA level and protein level, ER β and MFN2change with thesame trend, and they have linear relationship, while ER β doesn’t have linearrelationship with MMP2、MMP9and KLF4.