Expression Changes Of Survivin, P53 And HER-2 After Neoadjuvant Chemotherapy In Breast Cancer And Their Significance

Neoadjuvant chemotherapy(NCT) in breast cancer means especially preoperative chemotherapy in breast cancer.With the successively published mid-term outcomes based on several influential international multicentre randomized controlled clinical trials from the end of 20th century to the beginning of 21th century,NCT has been one of the standard options for local advanced breast cancer therapy.In recent years,following the development of recognition in the oncobiology,its serviceable range is extended to the treatment of early breast cancer.As an important ingredient in systematic therapy of breast cancer,NCT can not only shorten gross tumor volume and degrade TNM stage to be beneficial to perform breast-preserving surgery,but also help us evaluate the tumor response to a particular drug regimen in vivo and select postoperative chemotherapeutic regimen.Finally,NCT also provides drug sensitivity test model in vivo to study the molecular determinants which can predict therapeutic response.Studies on changes of molecular biology in tumour cells when NCT is effective can bear very important theoretical and practical values,which has become one of the current hot-spots in the systematic therapy of breast cancer.Molecular biological parameters which are used in the study of the response of NCT are concentrated on apoptosis-related factors(IAP,bcl-2),oncogenes(p53,HER-2), hormone receptor(ER/PR),drug-resistance-associated factors(MDR,GST),tumor cell proliferation factors(ki-67,PCNA),etc.Though there have been many researches concerning the correlation between the expressions of these parameters and expression changes and NCT,there have not been consensus conclusions to date.Survivin,as a new member in IAP family is considered to be the strongest molecular inhibiting apoptosis and may play an important role of inducing tumor cells apoptosis by chemotherapeutics. Survivin is negatively regulated by wild-type p53 at the mRNA and protein levels.P53 integrates with the survivin promoter and repress the combination of survivin promoter with the transcription factor E2F.On the other hand,survivin is positively regulated by mutant p53.Heterodimerization of HER-2 can result in the activation of intracellular signaling cascades PI3K/AKT pathway.As NF-κB,a transcription regulation factor of survivin,can be activated in the downstream of AKT,therefore,HER-2 can positively regulate the expression of survivin.How does NCT influence the expressions of survivin,p53 and HER-2 in vivo? Are the expression changes of p53 and HER-2,as significant regulatory factors of survivin expression,consistent with survivin expression change? All these questions will be studied in this paper.Materials and methods:Criteria for patients to be enrolled included:(1) patients should be at＜70 years of age and breast cancer were confirmed by CNB biopsy;(2) specimens were suitable for immunohistochemistry examination;(3) patients had not accepted hormonal therapy or local radiation therapy before NCT;(4) patients whose tumor volume could be measured; and(5) patients had received NCT with the same regimen(TAX 175mg/m~2,EPI 60 mg/m~2,dl,q3w).The patients,whose specimens were not enough for immunohistochemistry examination and who had the primary tumor resected because of operation biopsy,and obtained pathology complete remission after chemotherapy and less than two cycles of complete chemotherapy,were excluded.215 cases of breast cancer received NCT in Breast Disease Center,Southwest Hospital from January 2006 to July 2007.139 cases received TE regimen(TAX 175mg/m~2,EPI 60mg/m~2,dl,q3w).Ninety-two cases met the criteria and were involved in this study.All these patients were female,aged from 24 to 70 years,with the mean age of 44.9 years.Before neoadjuvant chemotherapy,14 cases were in T1 stage,55 cases in T2 stage,20 cases in T3 stage,and 3 cases in T4 stage.Axillary nodes metabasis occured in 55 cases.No distant metabasis was found in all cases. According to the tumor volume before chemotherapy 10 cases received 2 cycles of chemotherapy,59 cases 3 cycles and 23 cases 4 cycles.Before chemotherapy and operation all patients underwent ultrasound or breast X-ray examination for evaluating tumor size change.The effect of chemotherapy was evaluated according to the Response Evaluation Criteria in Solid Tumors(RECIST):complete response—the disappearance of all target lesions;partial response—at least a 30%decrease in the sum of the longest diameter of target lesions;progressive disease—at least a 20%increase in the sum of the longest diameter of target lesions;stable disease—neither sufficient shrinkage to qualify for partial response nor sufficient increase to qualify for progressive disease.All prechemotherapy core needle biopsy specimens and postchemotherapy resection specimens were got from our own experiment department.The IHC experiment specimens were fixed with 10%neutral formalin,embedded with paraffin,and sectioned in 4 um thickness.Fresh tissue samples were kept in liquid nitrogen at -80℃for use.The expressions of survivin,p53,and HER-2 were examined by immunohistochemical assay(S-P) in samples of breast cancer tissues before and after NCT.The expression intensity of the three molecules was evaluated by semiquantitative score.Among the 92 cases,43 cases were randomly selected,and their survivin mRNA in specimen was examined by RT-PCR assay.The data were analyzed using SPSS13.0 statistical software.Postoperative follow-up time was from April 2006 to July 2007.The outcomes were compared at two levels:the expression rates of survivin,p53, and HER-2 between the effective group and the ineffective group before NCT and the expression changes of the three factors in NCT,and the relationship between expression changes of the three factors was also analyzed.Results:1.The efficacy of NCT was defined by that cases had achieved complete remission and partial remission after NCT,and inefficacy by stable disease and progressive disease.In this study,14 cases(15.2%) achieved clinical complete remission(cCR),57 cases(62%) achieved clinical partial remission(cPR),and 21 cases(22.8%) achieved stable disease (SD).There was no progress disease(PD).The response rate(RR) was 77.2%.2.Survivin,p53 and HER-2 positive expression cases were 68(73.9%),46(50%) and 42(45.7%) respectively before NCT,and 50(54.3%),37(40.2%) and 36(39.1%) respectively after NCT.The survivin expression positive rate after NCT was significantly decreased(P＜0.05);the P53 and HER-2 expression positive rates were slightly decreased (P＞0.05).Before NCT,survivin mRNA expression-positive cases were 31,and expression-negative cases were 12;After NCT,survivin mRNA expression-positive cases were 21,and expression-negative cases were 22.The survivin mRNA positive rate after NCT was significantly decreased(P＜0.05).3.The survivin,p53,and HER-2 expression positive rates before NCT were 69%, 46.5%,and 47.9%respectively in the effective group,and 90.5%,61.9%,and 38.1% respectively in the ineffective group.The survivin expression before NCT was correlated with the effect of neoadjuvant chemotherapy(P＜0.05),but p53.and HER-2 expressions before NCT were not(P＞0.05).During the short-term follow-up period,we found distant metastasis in 3 cases and recurrence in the chest wall in 1 case with survivin expression positive.4.According to semi-quantitation score levels,after NCT,the expressions of survivin, p53,and HER-2 decreased in 31 cases,39 cases,and 32 cases,no expression change was found in 36 cases,30 cases,and 30 cases,and the expressions increased in 25 cases,23 cases,and 30 cases,respectively.Different expression changes of survivin were not correlated with the expression changes of p53 and HER-2(p=0.327 and 0.109, respectively).The response rates in survivin,p53,and HER-2 expression decrease group were 90.3%,82.1%,and 81.3%respectively;77.8%,73.3%,and 80%respectively in the no-expression-change group;and 60%,73.9%,and 70%respectively in the expression increase group.Different expression changes of survivin were correlated with the effect of NCT(P＜0.05),but p53 and HER-2 were not(P＞0.05).Conclusions:1.The effective rate of TE regimen neoadjuvant chemotherapy in the survivin expression-negative group is superior to the survivin positive group.There is no significant difference in the effective rate between the p53 and HER-2 negative groups and the p53 and HER-2 positive groups.2.After neoadjuvant chemotherapy with TE regimen,the expression positive rate of survivin is down-regulated obviously at the transcriptonal and translational levels.The different expression changes of survivin are correlated with the effect of neoadjuvant chemotherapy.There is no significant influence on the expressions of p53 and HER-2 and their expression changes are not correlated with the chemotherapy effect.Detecting. expression changes of survivin in TE rigemen may contribute to estimating the chemotherapy effect.3.Although experiments have confirmed that p53 and HER-2 are important regulatory factors,but we didn't find the expression changes of survivin were related to the expression changes of p53 or HER-2 after neoadjuvant chemotherapy in our study.This may be due to the expression change of survivin be co-regulated by multiple genes and pathways in chemotherapy.