The Study Of Three Circulating MicroRNAs Of Patient With Breast Cancer

BackgroundBreast cancer is the most common female malignancy, accounting for more than90%of breast cancer. From1970s, the morbidity number of breast cancer has beenoccupying the front row or the first place of the feminine malignant tumor, and wholeworld incidence increasing by2%every year. About1,200,000new cases femininebreast cancer has been diagnosed every year in the whole world, and about500,000females die of breast cancer. The morbidity number of breast cancer occupied7~10%the morbidity number of whole malignant. The morbidity of breast cancer in ourcountry is lower than the other country in the world and it was different in differentregion, the coastal city higher than hinterland, the developed economical regionhigher than the economical backwardness, the high population density city higherthan the low population density region.MicroRNAs(miRNAs) represent a class of short, non-coding and single-strandedRNA molecules with about21～25nucleotides. These miRNAs negatively regulategene expression by identifying the specific target mRNA, promoting mRNAdegradation and (or) inhibiting the translation on post-transcriptional level.MicroRNAs are intimately associated with ontogeny stem cell differentiation and theonset of disease. The function of miRNA in tumor diagnosis, treatment and prognosispredication had been discovered with deeper research recently. MiRNAs play animportant role in tumor biology behavior. It maybe an oncogene or tumor suppressor gene and would be a new therapeutic target in a few years. Reports said thatcirculating miRNAs were released by tumor cell and had close relationship withtumor clinical pathological feature. So the study of circulating miRNAs hassignificant influence on tumor early diagnosis, therapyment and prognosis predicationincluding breast cancer.Objective1. To explore the relationship of the expression of three breast cancer associatedmiRNAs among whole blood, plasma and serum.2. To analyze the expression of three breast cancer associated miRNAs betweenbreast cancer and non-breast cancer in whole blood, plasma and serum.3. To analyze the expression of three breast cancer associated miRNAs in thewhole blood, plasma and serum and explore the relationship between breast cancerpathological and the expression of three breast cancer associated miRNAs in thewhole blood, plasma and serum.Methods1．The cases registered in thyroid and breast surgery department of No.1People’s Hospital of Huai’an, the affiliated hospital of Nanjing Medical Universityaccording to the selected condition were enrolled. The cases’ basic documentincluding name, sexuality, age, the cases’ result of routine examination and thecases’ adjuvant examination including ultrasound examination，mammograms, wholebody bone scan were recorded. Blood sample including inanticoagulant andanticoagulant blood was collected before operation and the tissue sample wascollected during operation.2．Three mature miRNAs gene’s sequence were found out and the upstreamprimer sequence of three miRNAs and reference gene were designed and verified. The wholeblood, plasma and serum were isolated respectively form the collected blood sample.Total RNA and the part abundance of miRNA were extracted form whole blood,plasma and serum respectively for synthesizing cDNA, and the expression level ofthree miRNAs were measured by real-time qPCR.3．All tissue samples including breast cancer and nonbreast cancer tissueunderwent pathological examination, and breast cancer tissue underwentimmunohistochemisty examination for definitude the status of ER, PR in breastcancer tissue.Result1. The expression level of three breast cancer associated miRNAs among wholeblood, plasma and serum.The result of real-time qPCR demonstrated that the expression level of miRNAin serum was similar to that of in plasma, and there was no significant differencebetween plasma and serum, and the expression level of miRNA in whole blood wassignificantly higher than that of in plasma and serum.2. The expression level of three miRNAs between patient with breast cancer andnonbreast cancerThough analyzing the result of real-time qPCR of patient with breast cancer andnonbreast cancer, we found that the expression level of miR-155and miR-200c inpatients with breast cancer and nonbreast cancer were significant difference and theexpression level of miR-31had no significant difference between them.3. The expression level of three breast cancer associated miRNAs inplasma/serum and the clinical pathological feature of breast cancerThe expression level of miR-155in plasma and serum had a close relationshipwith breast cancer tumor size, breast cancer stage, lymph metastasis and state of ER and PR. The expression level of miR-200c in plasma and serum had a closerelationship with breast cancer tumor size, breast cancer stage, lymph metastasis andstate of ER, and there was no distinct relationship with state of PR. The expressionlevel of miR-31in plasma and serum was up-regulated with breast cancer tumor size,and there were no distinct relationship with breast cancer stage, lymph metastasis, thestate of ER and PR.4. The expression level of three breast cancer associated miRNAs in whole bloodand the clinical pathological feature of breast cancerThe expression level of miR-155in whole blood had a close relationship withbreast cancer tumor size, breast cancer stage, lymph metastasis and state of ER andPR. The expression level of miR-200c in whole blood had a close relationship withbreast cancer tumor size, breast cancer stage, lymph metastasis and state of ER, andthere was no distinct relationship with state of PR. The expression level of miR-31inwhole blood had close relationship with breast cancer tumor size and the state oflymph metastasis and there were no distinct relationship with breast cancer stage, thestate of ER and PR.Conclusions1. The expression level of miRNAs in whole blood were significantly higherthan that of in plasma＆serum and the expression level of miRNAs in serum weresimilar to that of in plasma.2. Compared with nonbreast cancer, the expression level of miR-155in wholeblood, plasma and serum of patient with breast cancer was up-regulated, that ofmiR-200c down-regulated, and there was no significant difference in point ofmiR-31.3. The expression of miR-31, miR-155and miR-200c in whole blood, plasma andserum have correlation with clinical pathological feature of patient with breast cancer.