Preliminary Study On The Gene Detection And Potential Targeted Drugs Of Refractory Recurrent Wilms Tumor In Children

BackgroundWilms tumor(WT)is the most common pediatric kidney tumor,accounting for approximately 90% of pediatric kidney tumors.It is a renal embryonal malignant tumor with usually good prognosis.Currently,through comprehensive treatment methods such as surgery,chemotherapy,and radiation therapy,the cure rate of WT can reach over 90%,but there are still about 15% of patients with recurrence.The survival rate of patients with relapsed or refractory(R/R)is extremely low,therefore,improving the survival of these patients has important clinical value and significance.Many studies have shown that the molecular genetics of WT is very complex,involving mutations in multiple genes,including WT1(on chromosome 11p13),WTX(on chromosome Xq11.1),and CTNNB1(encoding β-Genes for catenin,located on chromosome 3p22.1 and IGF2(located on chromosome 11p15);It also involves multiple chromosomal abnormalities,including an increase in LOH and 1q on 1p and 16 q.These changes in molecular genetics are closely related to the prognosis of WT patients.However,the research objects included in the current study are newly diagnosed WT patients,and there are few studies in the WT population with recurrence and refractory disease.Based on the current research status,we take the relapsed and refractory WT patients as the research object,further analyze the relationship between the clinicopathological characteristics of patients and their prognosis,and explore possible molecular genetics changes and potential therapeutic targets and targeted drugs,so as to provide new ideas and directions for the treatment of relapsed and refractory WT patients.Objective1.Preliminary exploration of gene mutation profiles in children with recurrent and refractory wilms tumor.2.Preliminary identification of potential therapeutic benefits associated with gene mutations,including the selection of targeted drug therapy,the possibility of immunotherapy,etc.3.Preliminary analysis of the clinicopathological characteristics and survival prognosis characteristics of single center children with recurrent and refractory WT.MethodsRetrospective collection of clinical data from 20 patients with nephroblastoma admitted to the Children’s Oncology Department of Sun Yat sen University Cancer Prevention and Treatment Center from March 2016 to May 2020.All patients have complete clinical data,are initially diagnosed under the age of 18,and have experienced disease recurrence after receiving standard first-line treatment in our hospital.This study has been approved by the Ethics Committee,obtaining informed consent from patients and guardians,and signing an informed consent form.Collect tumor samples and matched blood samples from patients and send them to a CAP(College of American Pathlogs,CAP)certified laboratory(The State Key Laboratory of Translational Medicine and Innovative Drug Development,Jiangsu Simcere Diagnostics Co.,Ltd)for genetic testing.Next generation sequencing(NGS)was performed using 539 cancer related genomes,and clinical data information of patients was included.Survival analysis was conducted using the Kaplan Meier method.ResultsThis study included a total of 20 children,including 9 girls and 11 boys,with a median age of 4.1 years(0.5-12 years)and a median follow-up time of 44.1 months(15.63-148.8 months).The median time for EFS was 26.2 months(4.7 to 46.3months).At the last follow-up,10 patients died,with a 5-year OS rate of 35.8 ±14.6%.The pathological types after recurrence include: 5 mixed type,1 interstitial type,3 embryonic type,2 epithelial type,and 9 unclassified types,indicating that the incidence of mixed type pathological types after recurrence is higher and the prognosis is worse compared to other pathological types.The efficacy of chemotherapy is correlated with OS and EFS(both P<0.001).According to gene mutation map detection,the top 6 genes with mutation frequencies are CTNNB1,CDK4,P53,ERBB2,TP53,and BTG2.The gene functions of mutations mainly involve genomic instability,PI3K/AKT pathway,receptor tyrosine kinase pathway,cell cycle and transcription factors,and tumor stem cell regulation.The results of chromosome CNV copy number analysis showed that the population often experienced an increase in chromosome copy numbers at 1q,12 p,12q,17 q,and 7p,while the copy numbers decreased at 11 q,4q,17 p,1p,and 16 q.Three cases(21.4%)of the children had pathogenic germline mutations,including one WT1 mutation and two FANCA mutations.The median tumor mutation burden(TMB)is 1.42 Muts/Mb(0-9.22 Muts/Mb).By searching the Onco KB database,10 out of 20 patients(50%)were matched with potential target drugs.The most common target gene mutations in this study included ERBB2(4 cases),FGFR(4cases),and CDK4(4 cases).One child’s tumor experienced 6 relapses and amplification of the CDK4 gene was detected.After using CDK4 inhibitors,their condition stabilized for 4 months.ConclusionsThis study preliminarily explored the mutation pattern of single center recurrent and refractory nephroblastoma patients in China,and found that the proportion of pathogenic germline mutations in this population is relatively high.The overall prognosis of patients with relapsed and refractory nephroblastoma is poor,but there are still 50% of patients who can be matched with targeted drugs.It is hoped that further prospective research will be conducted to explore whether the population of patients with relapsed and refractory nephroblastoma can benefit from these targeted drugs.