Correlation Of Microsatellite Instability And Mismatch Repair With Therapeutic Effect And Prognosis Of Colorectal Cancer

Background:Colorectal Cancer is a global cancer with high incidence,high degree of malignancy and a serious threat to human life and health.Mismatch Repair(MMR)gene can repair gene Mismatch,and it plays an important role in the cell replication phase,maintaining the stability of the genetic information.But microsatellite Instability(MSI)can occur if there is an error in MMR unable to repair cell replication process.DMMR/MSI-H is a marker indicating a good prognosis of phase ? CRC,and it also indicates that patients cannot benefit from 5-FU single-drug adjuvant chemotherapy.In clinical practice,the adjuvant treatment for postoperative colorectal cancer is still mainly oxaliplatin+5-FU or XELOX,such as the familiar FOLFOX or XELOX.In recent years,some researchers have found that 5-FU combined with other chemotherapy drugs can change the sensitivity of dMMR/MSI-H,especially the chemotherapy regimen containing oxaliplatin.To date,data on the correlation between MSI and specific chemotherapy regimens are still scarce.Objective:MMR expression and MSI type in colorectal cancer were investigated to further verify the consistency of MMR protein expression and MSI type.The correlation between MSI expression and clinicopathological characteristics was analyzed,and the difference in efficacy was observed in patients with different MSI and different chemotherapy regimens.Method:Using immunohistochemistry(IHC)in 130 cases of MMR protein expression in colorectal cancer tissue samples,at the same time using polymerase chain reactions(PCR)method to detect colorectal cancer tissues of MSI classification,analysis of MSI correlation expression and clinicopathological characteristics,further verify the MMR protein expression with MSI classification consistency.At the same time,the effects of different chemotherapy regimens on colorectal cancer were observed by observing and comparing different recurrence free survival(DFS)in patients with different stages,diflerent MSI and different ehemotherapy regimens.Results:The high expression rate of MMR in colorectal cancer tissues was 73.1%(95/130),and the detection rate of MSI-H expression was 23.8%(31/130).So MMR expression and MSI expression contain correlation(P<0.001).MSI type had no significant correlation with age(P?0.639),gender(P=0.378),location(P=0.418),degree of differentiation(P=0.286)and stage(P=0.225).According to survival analysis,FOLFOX4 showed that the recurrence time of the MSI-H group was less than that of the non-MSI-H group,and no statistical difference between the MSI-H group and the non-MSI-H group was found in the XELOX chemotherapy group and the untreated group.Conclusion:1.The expression level of MMR protein is highly consistent with the status of MSI,so immunohistochemistry can be used as a first-line screening method.2.XELOX chemotherapy is more recommended for MSI-H patients with indications of chemotherapy.