| [Background and objectives] The bio-chip technology has been widely used in thefield of biology., According to the different biological substances which are spread onchip, it is divided into gene chip, protein chip, the cell chip, tissue chip. The tissuechip, which was known as the tissue micro-array, is from a plurality of different tissuespecimens putting on the same slides, which was used to histology research in situand has a fast, small volume, simultaneous, high flux, rapid time-saving features.Tissue microarray technology has been applied to study human diseases, humangenomics and the development of new drugs, tracking the treatment process andother new areas.In tumor pathology, tissue microarray technology is mainly used to detectingtumor-associated genes and their expression products in different types of the sametumor, different stages of the same types. To explore the factors related to tumordifferentiation, metastasis, prognosis and recurrence, it can provide a new theoreticalsupport for clinical decision.Breast cancer is the most common female malignancy, morbidity of America patientswith breast cancer is about30%in2011. In China, Beijing, Shanghai and other majorcities, statistics show that the morbidity of breast cancer, which is the most commonmalignant tumor for female, is increasing.The occurrence, development and prognosis of breast cancer are closely related toepigenetic modification. Epigenetics is a subject which study the gene expressionwithout gene sequence changing, which occurs in the process of transcription of DNAand translating of mRNA, including DNA methylation, histone modifications andnon-coding RNA and so on. It not only affects gene expression, gene regulation, andgenetic, but also has an important role on the occurrence and prevention of cancer, immune diseases and so on. It is an important field of life science.NSD2is a histone lysine transmethylase containing SET domain, which belongs tothe NSD（nuclear receptor binding SET domain containing）protein family. Studiesshow that the SET domain is homologous to the classical H3K36methylase SET2,from which we inferred that NSD2may work by catalyzing the methylation ofH3K36. The people pay attention to the close relationship between NSD protein anddiseases. Studies have shown that the carcinogenesis and development of variouscancers are closely related to the high expression of NAD2.EZH2is an evolutionarily highly conserved gene of PcG family, which is the onlycatalyst for H3K27methylation. It is related to histone methylation and has animportant role in cell growth and development. Its role in tumorigenesis has alsobeening attention. Studies have discovered that EZH2expresses highly in varioustumor cell lines, and the genes in the embryonic stem cells which are regulated byEZH2are more likely to deactivate by DNA methylation in tumour cells.There is little research about NSD2and EZH2expression and biogenetics in breastcancer,so tissue microarray technology and immunohistochemistry were used todetect and analyze the histone methylation transferase EZH2and NSD2of breastcancer to explore the development and outcome of breast cancer under high and lowlevel of EZH2and NSD2expression in breast cancer. It will become a new marker forbreast cancer diagnosis and prognosis[Materials and methods]1.The wax tissues which confirmed with breast cancer wereselected from Pathology of the affiliated Hospital of Dali College which kept since2006, including120cases of invasive ductal carcinoma,40cases of special cancer, atotal of160cases. And tissues which diagnosed with benign breast tumors, including146cases of breast adenosis and24cases of fibroadenoma, a total of230cases, wereselected.2.Tissue microarray was made with wax tissues.3.The expression of histonemethylation transferase NSD2and EZH2in breast cancer was detected with IHC..[Result]1. Basic clinical information1.1All breast-cancer patients were female.170cases of the breast samples including146cases of the breast-cancer patients which theage was from29to80years and the median age was48;24cases of the benign breast disease patients which were28to57years old and the median age was42, were frombiopsy and excision,1.2Pathologic histology:126cases were invasive ductalcarcinoma,12cases were intraductal carcinoma,8cases were lobular carcinoma andspecific cancer; pathological grades:35cases were gradeⅠ，71cases were gradeⅡ，20cases were grade Ⅲ；lymph node metastasis：74cases were metastasized，72cases were of no lymph node metastasis。2．The results of tissue microarray: thetissue microarray of3×4matrix totaled16. Microscopic observation with HE stainingshowed that there were no flaking, reversing or floating in the microarray points. Thepoints remained intact in the microarray, while several points were slightly displacedin the matrix.3. Immunohistochemical results:170cases of microarray tissue in thisexperiment were carried out immunohistochemical staining for NSD2and EZH2protein. The results were as follows:3.1The expression of the histonetransmethylase NSD2:3.1.1The ratio of positive expression of NSD2protein in the146cases of breast cancer was79.5%（116/146）, while its in the24cases of benignbreast disease was12.5%（3/21）. The positive ratio of NSD2in the breast cancertissue was obviously higher than that in the benign breast disease. There was asignificant difference in the expression of NSD2between breast cancer and benignbreast disease(P＜0.05)；3.1.2There was a significant difference in the positive rateof the histone transmethylase NSD2between different pathological grades of breastcancer(P＜0.01). The grade I of NSD2positive rate was62.9%,grade II was84.5%，grade III was95.0%, which indicated that the pathological higher grade of breastcancer matched with the higher positive expression of NSD2;3.1.3There was asignificant difference in the NSD2positive rate between lymph node metastasis ornot(P＜0.01). The positive rate was89.2%when there was breast cancer with lymphnode metastasis, while it was55.2%without lymph node metastasis;3.1.4There wasno significant difference in the NSD2positive rate between different nationalities,ages or pathologic histology(P＞0.05).3.2The expressions of the histonetransmethylase EZH2:3.2.1Among the146cases of breast cancer tissues in thisexperiment, the rate of positive expression of EZH2protein was82.2% （120/146）,while that of EZH2in the24cases of benign breast disease was16.7%（4/21）. The positive rate of EZH2in the breast cancer tissue was obviously higherthan that in the benign breast disease. There was a significant difference in theexpression of EZH2between breast cancer and benign breast disease(P＜0.05);3.2.2There was a significant difference in the positive rate of the histone transmethylaseEZH2between different pathological grades in the breast cancer(P＜0.01). The gradeI of EZH2positive rate was62.9%,grade II was90.1%，grade III was100.0%, whichindicated that the pathological higher grade of breast cancer matched with the higherpositive expression of EZH2.3.2.3There was a significant difference in the EZH2positive rate between lymph node metastasis or not(P＜0.01). The EZH2positive ratewas94.6%when there was breast cancer with lymph node metastasis, while it was56.3%without lymph node metastasis;3.2.4There was no significant difference inthe EZH2positive rate between different nationalities, ages or pathologic histology(P＞0.05).3.3NSD2and EZH2proteins coexpression and clinical pathologicalanalysis:3.3.1There was a significant difference in NSD2and EZH2proteinscoexpression between different pathologic histology, pathological grades and lymphnode metastasis or not of the patients suffering breast cancer（P＜0.05）;3.3.2Therewas no significant difference in NSD2and EZH2proteins coexpression betweendifferent nationalities, ages or pathologic histology of the patients suffering breastcancer (P＞0.05).[Conclusion] NSD2and EZH2protein were analyzed through immunohistochemicalstaining with tissue microarray samples（including146cases of breast cancer tissueand24cases of benign breast lesions）. The conclusion is as follows:1. Comparedwith traditional technique, the tissue microarray with HE staining showed that thesensitivity and accuracy is consistent with that of traditional methods. In addition, thetissue microarray technology is characterized by efficiency, high throughput, savingdetection reagent, experimental error reduction, easy standardization, increasingcomparability, etc. As a result, the tissue microarray technology is superior totraditional tissue sectioning technologies, so it can be applied to cancer biologystudies.2. NSD2and EZH2are highly expressed in the microarray of breast cancer and have a close relationship with pathological grades and lymph node metastasis.They play important roles in the carcinogenesis and development of breast cancers,which can serve as reference indicators for determining the grade malignancy anddevelopment of breast cancer. |
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