| Objective:To explore the relationship between KRAS and BRAF gene mutations and their clinicopathological characteristics in colorectal cancer(CRC),and to understand the clinicopathological characteristics and survival prognosis of CRC patients with different gene mutation types,so as to provide theoretical basis for the diagnosis and treatment of the CRC patients.Methods:Tumor specimens of 1183 patients with CRC surgically resected and pathologically confirmed in Guangzhou First People’s Hospital from March 2014 to December 2019 were collected.All the pathological tissues were referring to the TNM tumor staging standard of UICC/AJCC 8th edition,and the pathological features and clinical stages of the samples were evaluated by pathologists of our hospital.Amplification-refractory mutation system polymerase chain reaction(ARMS-PCR)technique was used to detect the mutation of exon 2,3,4 of the KRAS gene and V600 E site of exon 15 of the BRAF gene.Relevant immunohistochemical indexes were detected by immunohistochemistry.KRAS,BRAF gene mutation and gender,age,TNM stage,primary tumor site,tumor number,maximum tumor diameter,general type,degree of differentiation,pathological type,and mismatch repair(MMR),vascular infiltration,nerve infiltration,Ki-67,P53,Villin,CDX2,CK7 and CK20 were detected by immunohistochemistry.At the same time,the pathological characteristics of two mutation types of CRC with different MMR were compared.GSEA gene enrichment was used to analyze the expression of related genes.Follow-up survey and prognosis survival analysis were performed for these patients with CRC.Results:1.In 1183 CRC patients,the total mutation rate of KRAS gene was 43.87%(519/1183),and the highest mutation rate was 41.76%(494/1183)in exon 2,1.01%(12/1183)in exon 3 and 1.01%(12/1183)in exon 4.The co-mutation rate of exon 3and 4 was 0.08%(1/1183).BRAF gene V600 E codon mutation rate was 4.73%(56/1183).2.Compared with patients with wild-type(WT)CRC,KRAS mutation CRC patients had a higher proportion in female and the right colon,especially in the ascending colon and transverse colon of the right colon.The proportion of moderately to poorly differentiated was higher.The proportion of mucinous adenocarcinoma and signet ring cell carcinoma was higher.The proportion of protruded type and infiltrating type was higher(P<0.05).3.Compared with WT CRC patients,BRAF gene mutations in CRC patients were more likely to occur in female and the right colon,especially in the ascending colon and transverse colon of the right colon.The number of multiple tumors,moderately to poorly differentiated and poorly differentiated tumors was higher.The proportion of mucinous adenocarcinoma and signet ring cell carcinoma was higher.The proportion of T4 stage was higher.The percentage of d MMR,positive vascular infiltration and negative CDX2 was higher(P<0.05).4.Compared with KRAS mutation CRC,BRAF mutation CRC had a higher proportion of multiple tumors and a higher proportion of tumors occurring in the colon.The proportion of moderately to poorly differentiation and poorly differentiation degree was higher,the proportion of d MMR was higher,and the proportion of negative CDX2 expression was higher(P<0.05).5.In KRAS mutantion CRC,Compared with CRC patients with codon 13 mutation,CRC patients with codon 12 mutation had a higher age of onset,a hihger proportion of T4 stage and lower proportion of d MMR(P<0.05).6.In KRAS mutation CRC,compared with p MMR CRC,d MMR CRC patients had a higher age of onset,a higher proportion of T2 stage,a higher proportion of no lymph node metastasis,a higher proportion of maximum tumor diameter≥5 cm,pathological types of mucinous adenocarcinoma of the ingredient ratio is higher,and most of them were more likely to occurr in the colon,especially in the ascending colon and transverse colon of the right colon.In BRAF mutation CRC,compared with p MMR CRC,d MMR CRC patients had a higher age of onset,a higher proportion of T4 stage,and a higher proportion of no lymph node metastasis(N0 stage),and most of them were more likely to occur in the right colon(P <0.05).7.Compared with KRAS mutantion and WT CRC,BRAF mutantion CRC showed more inflammatory responses in the tumor microenvironment(P<0.05).8.The results of multivariate Cox regression analysis of CRC death risk factors showed that KRAS mutation BRAF mutation,TNM stage and the age of patients were independent predictable death risk factors of CRC patients.9.By comparing the prognostic survival analysis of the different genotypes of CRC,We found that compared with WT CRC,KRAS mutation CRC and BRAF mutation CRC had a worse prognosis(P=0.005).Conclusion:Compared with WT CRC,the proportion of mucinous adenocarcinoma component was increasing in KRAF mutation CRC.Compared with WT CRC,the proportion of d MMR,moderately to poorly differentiated and poorly differentiated,and the proportion of mucinous adenocarcinoma component were increasing in BRAF mutantion CRC.Compared with KARS mutation CRC,the proportion of d MMR and moderately to poorly differentiated and poorly differentiated were increasing in BRAF mutation CRC.d MMR status affected different T stage of KRAS and BRAF mutation CRC.BRAF mutantion CRC had more inflammatory responses in tumor microenvironment.Both KRAS and BRAF gene mutations suggested a poor prognosis.Therefore,routine detection of KRAS and BRAF gene status,mutation type and mismatch repair function would provide a theoretical basis for individualized precise targeted treatment of the CRC patients. |
