Expression Of RMP In Intrahepatic Cholangiocarcinoma And Its Effect On Prognosis

BackgroundCholangiocarcinoma can be divided into intrahepatic cholangiocarcinoma and extrahepatic cholangiocarcinoma.Intrahepatic cholangiocarcinoma(ICC)often occurs in the liver away from the confluence of the left and right hepatic ducts and is a kind of adenocarcinoma caused by carcinoma of covering epithelium of secondary bile duct and its branches.ICC in histopathology can be divided into well differentiated adenocarcinoma,poorly differentiated adenocarcinoma,poorly differentiated adenocarcinoma and undifferentiated adenocarcinoma and adeno-squamous carcinoma.ICC is the second most common liver malignancy,accounting for about 5% to 15% of liver malignancies.Some studies have shown that the incidence and mortality of ICC have been increasing in recent years.Among them,the number of ICC patients in China accounts for about 55% of the total number of ICC in the world.ICC always has a high degree of malignancy and usually poor prognosis,less than 5% of 5-year survival rate,only 4-6 months of the average survival time.ICC treatment is mainly dominated by surgery.Although 5-year survival rate was lower after radical resection,performing radical resection as soon as possible is the only effective treatment program.R0 resection surgery,that is,no tumor invasion at the margin,can reach a 35.6% of 3-year survival rate after surgery and a 20.1% of 5-year survival rate.Liver transplantation treatment for ICC is still controversial.Since most patients have been on the stage of cancer progression for the first time of diagnosis,they have lost the chance of radical resection.Although the 1-year survival rate has improved significantly over the past few decades,there has been no significant change in the 5-year survival rate.Currently,the 5-year survival rate after radical resection for ICC is worse than that of hepatocellular carcinoma(HCC).The available data suggest that ICC morbidity may be associated with the following risk factors: fibrous polycystic liver disease,primary sclerosing cholangitis(PSC),hepatitis virus infection,intrahepatic bile duct stones,chemical carcinogens contact,insect infection,obesity,diabetes,smoking and so on.At present,the researches on molecular mechanism of the pathogenesis of ICC are also not deep enough and the specific mechanism is still unclear.The previous studies have shown that it may be associated to the following reasons: the cholestasis caused prolonged stimulation of bile duct epithelial cells and the chronic biliary inflammation caused bile duct epithelial stimulation,causing the release of inflammatory factors and activation of growth factors,which caused cell proliferation and apoptosis-related gene regulation imbalance,thereby leading to cell tumor proliferation.The signal pathways involved are: MAPK,HGF,STAT,met,IL-6,EGF,c-erbB-2,p53 and so on.Acquired cytological changes include apoptotic escape,infinite proliferation,enhanced invasion and metastasis,and enhanced angiogenesis.Compared with studies of hepatocellular carcinoma,there is still a great shortage in the studies on the formation mechanism,biological characteristics,key factors and clinical prognosis of ICC,and it is of great significance to further study and explore its pathogenesis.RMP(RPB5-mediating protein)is a regulatory protein of subunit 5(RPB5)of RNA polymerase II,also known as C19orf2 or URI.It is an RPB5 regulatory protein cloned by Cheong et al.using the recombinant human RPB5 probe in the cDNA library of the hepatoma cell line.Later studies found that in gene transcription,genome stability,apoptosis and ovarian cancer,endometrial cancer,gastric cancer and other tumors,RMP have played a very important role in their occurrence and development,but the specific mechanisms need further study.The identified biological functions of RMP have been summarized as follows:(1)RMP plays a role in the regulation of gene transcription: RMP is a binding protein of hepatitis B virus X protein and transcription factor IIB(TFIIB),which may be a radical involved in transcriptional activity of RNA polymerase II.In addition,RMP can bind to TFIIF to supplement and regulate transcriptional activity.There are also studies that show RMP is associated with mTOR-dependent nutrient regulation of metabolism;(2)RMP plays a role in apoptosis: studies have shown that RMP can form complexes with PP1? on mitochondria,thereby influencing S6 kinase 1(S6K1)-mediated signaling pathways;(3)RMP plays a role in HCC cells: studies have shown that RMP plays a radiotherapy resistance role in HCC,which can affect the growth and apoptosis of HCC cell lines.Recent studies have shown that RPB5-mediating protein(RMP)of RNA polymerase II subunit 5 is highly expressed in HCC.The use of interfering techniques to inhibit the expression of RMP in HCC can be found to significantly inhibit the growth of HCC cells and the rate of them entering to G2 / M phase and to significantly inhibit HCC cell cloning ability and reduce or completely inhibit in vivo tumorigenic ability of HCC cells.The hyperexpression of RMP was correlated with the clinicopathological features and prognosis of HCC patients.The level of RMP in the tumor can be used to assess the prognosis of patients with HCC and can be used to assist in choosing which part of patients is suitable for TACE adjuvant therapy to avoid recurrence.At present,the expression of RMP in intrahepatic cholangiocarcinoma and the effect of RMP on ICC cell growth,metastasis and invasion have not been reported.PurposeOur previously pre-experimental immunohistochemical results showed that ICC in the RMP is also in a significantly higher expression level.Thus we conclude that RMP may play an important role in the tumorigenesis and progression of ICC.The expression of RMP in ICC tissues and its relationship with prognosis were examined in this study by large sample,and the effects of RMP expression on ICC cell migration,invasion and proliferation were also examined.It can be speculated that RMP can be used as a prognostic indicator of intrahepatic cholangiocarcinoma.Method1.The study included a total of 462 cases of patients initially-diagnosed as and postoperatively-pathological-diagnosis-confirmed intrahepatic cholangiocarcinoma.After excluding postoperatively-pathological-diagnosis-confirmed patients with ICC mixed with hepatocellular carcinoma,the clinical and pathological data of patients were summarized,followed by follow-up,so as to record the patients' tumor recurrence and survival status.2.The expression of RMP in the adjacent tissues and cancer tissues of intrahepatic cholangiocarcinoma was detected by immunohistochemistry(IHC).3.The Leica's DM IRE2 microscope was used to observe immunohistochemical sections of ICC patients,and the company's FC420 CCD camera was used to take and store pictures with x100 magnifier.4.The IOD values were taken from the photos of ICC immunohistochemical sections by using Image-Pro Plus v6.0 software(Media Cylernetics,Bethesda,MD.USA),and the area was measured to obtain the IOD/area value,the average IOD value of each immunohistochemical sections photo is calculated scientifically.5.By using IBM SPSS Statistics 22.0(IBM,Chicago,IL),X-tile method,chi-square test,prognostic analysis,univariate and multivariate cox analysis,ROC curve and other statistical methods,the correlation between ICC patients' IHC IOD/area values and clinicopathological data,so as to clarify the effect of RMP on the prognosis of intrahepatic cholangiocarcinoma.6.Through the RMP interference method,it further observed its effect on biological behavior of intrahepatic cholangiocarcinoma and further clarified its effect on intrahepatic cholangiocarcinoma migration,invasion and proliferation,so as to lay a good foundation for the research on the mechanism in the future.Result1.The immunohistochemical results of RMP in the intrahepatic cholangiocarcinoma tissue showed: it was expressed in both tumor cell nuclei and cytoplasm.2.By taking IOD value from RMP immunohistochemical sections photos using Image-Pro Plus v6.0 software,and measuring the area,and obtaining its IOD/area value,the results showed that RMP expression in cancer tissue of intrahepatic cholangiocarcinoma was significantly higher than that in adjacent tissues.3.By univariate and multivariate Cox analysis,in 462 cases of patients undergoing hepatectomy for intrahepatic cholangiocarcinoma,the tumor size(HR: 1.667;95% CI: 1.317-2.110),number of tumors(HR: 1.558;95%CI: 1.198-2.026),TNM staging(HR: 1.209;95% CI: 1.086-1.347),serum CEA content(HR: 1.369;95% CI: 1.060-1.768)were independent risk factors for the overall survival time of patients post the surgery;the tumor size(HR: 1.953;95% CI: 1.497-2.549),number of tumors(HR: 1.636;95% CI: 1.228-2.179),TNM staging(HR: 1.207;95% CI: 1.070-1.361),RMP content(IOD / area)(HR: 1.493;95% CI: 1.046-2.130)were independent risk factors for postoperative recurrence in patients.The influence of difference of RMP expression in tissue sections of patients with intrahepatic cholangiocarcinoma on the postoperative recurrence of patients was significantly different.4.Via RMP interference,the results showed that the ability of migration,metastasis and proliferation of cholangiocarcinoma cells had a significant decrease after RMP interference,which indicated that RMP plays an important role in the growth and metastasis of cholangiocarcinoma cells.ConclusionsThis study demonstrates that RMP is highly expressed in intrahepatic cholangiocarcinoma and such hyperexpression is associated with postoperative recurrence in ICC patients and is an independent risk factor for postoperative recurrence in ICC patients.It also shows that RMP plays an important role in the growth and metastasis of ICC.This study suggests that RMP can serve as a reliable predictor for the recurrence of ICC.