Construction of SNP genetic maps based on targeted next-generation sequencing and QTL mapping of vital agronomic traits in faba bean(Vicia faba L.)

Owing to the limitation of a large genome size(~13 Gb),the genetic and gene mapping studies on faba bean(Vicia faba L.)are lagging far behind those for other legumes.In this study,we selected three purified faba bean lines(Yundou 8137,H0003712,and H000572)as parents and constructed two F2 populations.These two F2 populations,namely 167 F2 plants in Pop1(Yundou 8137×H0003712)and 204 F2 plants in Pop2(H000572×Yundou 8137),were genotyped using a targeted next-generation sequencing(TNGS)genotyping platform,and two high-density single nucleotide polymorphisms(SNP)genetic linkage maps of faba bean were constructed.The map constructed from Pop1 contained 5103 SNPs with a length of 1333.31 cM and an average marker density of 0.26 cM.The map constructed from Pop2 contained 1904 SNPs with a greater length of 1610.61 cM.In these two F2 populations,QTL mapping identified 98 QTLs for 14 agronomic traits related to the flowers,pods,plant types and grains.The two maps were then merged into an integrated genetic linkage map containing 6895 SNPs,with a length of 3324.48 cM.These results not only lay the foundation for fine mapping and map-based cloning of related genes,but can also accelerate the molecular marker-assisted breeding of faba bean.

Targeted next-generation sequencing identifies a novel nonsense mutation in ANK1 for hereditary spherocytosis:A case report

BACKGROUND Hereditary spherocytosis(HS)is characterized by anemia,jaundice,splenomegaly,and cholelithiasis,and is caused by abnormal genes encoding red blood cell membrane components.The most common mutations found in HS are in the ANK1 gene.CASE SUMMARY A 4-mo-old girl was admitted to our hospital with pallor that had lasted for more than 2 mo.She presented with jaundice,anemia and splenomegaly.A heterozygous mutation of ANK1(exon23:c.G2467T:p.E823X)was identified,and the mutation was determined to be autosomal dominant.This mutation is linked to the relatively serious anemia she had after birth;this anemia improved with age.CONCLUSION The utilization of next-generation sequencing may assist with the accurate diagnosis of HS,especially in atypical cases.

Diagnostic Value of Targeted Next-generation Sequencing in Pulmonary Mycobacterial Infections

Objective This study aimed to explore the diagnostic value of novel technique-targeted next-generation sequencing(tNGS)of bronchoalveolar lavage fluid(BALF)in pulmonary mycobacterial infections.Methods This retrospective study was conducted on patients who underwent bronchoscopy and tNGS,smear microscopy,and mycobacterial culture of BALF.Patients with positive Mycobacterium tuberculosis(MTB)culture or GeneXpert results were classified into the tuberculosis case group.Those diagnosed with nontuberculous mycobacteria(NTM)-pulmonary disease(NTM-PD)composed the case group of NTM-PD patients.The control group comprised patients without tuberculosis or NTM-PD.Sensitivity,specificity,and receiver operating characteristic(ROC)curves were used to evaluate the diagnostic performance.Results For tuberculosis patients with positive mycobacterial culture results,the areas under the ROC curves(AUCs)for tNGS,GeneXpert,and smear microscopy were 0.975(95%CI:0.935,1.000),0.925(95%CI:0.859,0.991),and 0.675(95%CI:0.563,0.787),respectively.For tuberculosis patients with positive GeneXpert results,the AUCs of tNGS,culture,and smear microscopy were 0.970(95%CI:0.931,1.000),0.850(95%CI:0.770,0.930),and 0.680(95%CI:0.579,0.781),respectively.For NTM-PD,the AUCs of tNGS,culture,and smear-positive but GeneXpert-negative results were 0.987(95%CI:0.967,1.000),0.750(95%CI:0.622,0.878),and 0.615(95%CI:0.479,0.752),respectively.The sensitivity and specificity of tNGS in NTM-PD patients were 100%and 97.5%,respectively.Conclusion tNGS demonstrated superior diagnostic efficacy in mycobacterial infection,indicating its potential for clinical application.

Impact of next-generation sequencing on antimicrobial treatment in immunocompromised adults with suspected infections

BACKGROUND:Prompt pathogen identification can have a substantial impact on the optimization of antimicrobial treatment.The objective of the study was to assess the diagnostic value of next-generation sequencing(NGS)for identifying pathogen and its clinical impact on antimicrobial intervention in immunocompromised patients with suspected infections.METHODS:This was a retrospective study.Between January and August 2020,47 adult immunocompromised patients underwent NGS testing under the following clinical conditions:1)prolonged fever and negative conventional cultures;2)new-onset fever despite empiric antimicrobial treatment;and 3)afebrile with suspected infections on imaging.Clinical data,including conventional microbial test results and antimicrobial treatment before and after NGS,were collected.Data were analyzed according to documented changes in antimicrobial treatment(escalated,no change,or deescalated)after the NGS results.RESULTS:The median time from hospitalization to NGS sampling was 19 d.Clinically relevant pathogens were detected via NGS in 61.7% of patients(29/47),more than half of whom suffered from fungemia(n=17),resulting in an antimicrobial escalation in 53.2% of patients(25/47)and antimicrobial de-escalation in 0.2% of patients(1/47).Antimicrobial changes were mostly due to the identification of fastidious organisms such as Legionella,Pneumocystis jirovecii,and Candida.In the remaining three cases,NGS detected clinically relevant pathogens also detected by conventional cultures a few days later.The antimicrobial treatment was subsequently adjusted according to the susceptibility test results.Overall,NGS changed antimicrobial management in 55.3%(26/47)of patients,and conventional culture detected clinically relevant pathogens in 14.9% of the patients(7/47).CONCLUSION:With its rapid identification and high sensitivity,NGS could be a promising tool for identifying relevant pathogens and enabling rapid appropriate treatment in immunocompromised patients with suspected infections.

Bronchoalveolar lavage fluid metagenomic next-generation sequencing assay for identifying pathogens in lung cancer patients

Background:For patients with lung cancer,timely identification of new lung lesions as infectious or non-infectious,and accurate identification of pathogens is very important in improving OS of patients.As a new auxiliary examination,metagenomic next-generation sequencing(mNGS)is believed to be more accurate in diagnosing infectious diseases in patients without underlying diseases,compared with conventional microbial tests(CMTs).We designed this study tofind out whether mNGS has better performance in distinguishing infectious and non-infectious diseases in lung cancer patients using bronchoalveolar lavagefluid(BALF).Materials and Methods:This study was a real-world retrospective review based on electronic medical records of lung cancer patients with bronchoalveolar lavage(BAL)and BALF commercial mNGS testing as part of clinical care from 1 April 2019 through 30 April 2022 at The First Affiliated Hospital of Sun Yat-sen University.164 patients were included in this study.Patients were categorized into the pulmonary non-infectious disease(PNID)group(n=64)and the pulmonary infectious disease(PID)group(n=100)groups based onfinal diagnoses.Results:BALF mNGS increased the sensitivity rate by 60%compared to CMTs(81%vs.21%,p<0.05),whereas there was no significant difference in specificity(75%vs.98.4%,p>0.1).Among the patients with PID,bacteria were the most common cause of infection.Fungal infections occurred in 32%of patients,and Pneumocystis Yersini was most common.Patients with Tyrosine kinase inhibitors(TKIs)therapy possess longer overall survival(OS)than other anti-cancer agents,the difference between TKIs and immuno-checkpoint inhibitors(ICIs)was insignificant(median OS TKIs vs.ICIs vs.Anti-angiogenic vs.Chemo vs.Radiotherapy=76 vs.84 vs.61 vs.58 vs.60).Conclusions:our study indicates that BALF mNGS can add value by improving overall sensitivity in lung cancer patients with potential pulmonary infection,and was outstanding in identifying Pneumocystis infection.It could be able to help physicians adjust the follow-up treatment to avoid the abuse of antibiotics.

Brain abscess from oral microbiota approached by metagenomic next-generation sequencing: A case report and review of literature

BACKGROUND Brain abscess is a serious and potentially fatal disease caused primarily by microbial infection.Although progress has been made in the diagnosis and treatment of brain abscesses,the diagnostic timeliness of pathogens needs to be improved.CASE SUMMARY We report the case of a 54-year-old male with a brain abscess caused by oral bacteria.The patient recovered well after receiving a combination of metagenomic next-generation sequencing(mNGS)-assisted guided medication and surgery.CONCLUSION Therefore,mNGS may be widely applied to identify the pathogenic microor-ganisms of brain abscesses and guide precision medicine.

Metagenomic next-generation sequencing may assist diagnosis of osteomyelitis caused by Mycobacterium houstonense:A case report

BACKGROUND Mycobacterium houstonense(M.houstonense)belongs to the nontuberculous mycobacterium group.Infection caused by M.houstonense is prone to recurrence.CASE SUMMARY We present a patient who was diagnosed with osteomyelitis caused by M.houstonense and treated with a combination of cefoxitin,and amikacin combined with linezolid.CONCLUSION The emergence of metagenomic next-generation sequencing(NGS)has brought new hope for the diagnosis and treatment of listeria meningitis.NGS can analyze a large number of nucleic acid sequences in a short time and quickly determine the pathogen species in the sample.Compared with traditional cerebrospinal fluid culture,NGS can greatly shorten the diagnosis time and provide strong support for the timely treatment of patients.Regarding treatment,NGS can also play an important role.Rapid and accurate diagnosis can enable patients to start targeted treatment as soon as possible and improve the treatment effect.At the same time,by monitoring the changes in pathogen resistance,the treatment plan can be adjusted in time to avoid treatment failure.

Diagnosis of Acute Q Fever in an Elderly Patient Using Metagenomic Next-Generation Sequencing:A Case Report

Query fever(Q fever)is a globally spread zoonotic disease caused by Coxiella burnetii,commonly found in natural foci but rarely seen in Hebei Province.The clinical manifestations of Q fever are diverse and nonspecific,which often leads to missed or incorrect diagnoses in clinical practice.This article reports a case of acute Q fever diagnosed in an elderly patient using metagenomic next-generation sequencing.

Prevalence of gene mutations in a Chinese 46,XY disorders of sex development cohort detected by targeted next-generation sequencing

46,XY disorders of sex development(DSD)is characterized by incomplete masculinization genitalia,with gonadal dysplasia and with/without the presence of Mullerian structures.At least 30 genes related to 46,XY DSD have been found.However,the clinical phenotypes of patients with different gene mutations overlap,and accurate diagnosis relies on gene sequencing technology.Therefore,this study aims to determine the prevalence of pathogenic mutations in a Chinese cohort with 46,XY DSD by the targeted nextgeneration sequencing(NGS)technology.Eighty-seven 46,XY DSD patients were enrolled from the Peking Union Medical College Hospital(Beijing,China).A total of fifty-four rare variants were identified in 60 patients with 46,XY DSD.The incidence of these rare variants was approximately 69.0%(60/87).Twenty-five novel variants and 29 reported variants were identified.Based on the American College of Medical Genetics and Genomics(ACMG)guidelines,thirty-three variants were classified as pathogenic or likely pathogenic variants and 21 variants were assessed as variants of uncertain significance.The overall diagnostic rate was about 42.5%based on the pathogenic and likely pathogenic variants.Androgen receptor{AR),steroid 5-alpha-reductase 2(SRD5A2)and nuclear receptor subfamily 5 Group A member 1(NR5A1)gene variants were identified in 21,13 and 13 patients,respectively.The incidence of these three gene variants was about 78.3%(47/60)in patients with rare variants.It is concluded that targeted NGS is an effective method to detect pathogenic mutations in 46,XY DSD patients and AR,SRD5A2,and NR5A1 genes were the most common pathogenic genes in our cohort.

A genomic study of adult-onset idiopathic hypoparathyroidism in Chinese by targeted next-generation sequencing

Objective To screen gene mutation in adult-onset hypoparathyroidism in Chinese through the targeted nextgeneration sequencing(NGS).Methods We recruited 17patients with adult-onset hypoparathyroidism who were regularly followed or newly diagnosed at our centre during the past one year.Nine of them developed hypercalciuria during the treatment with calcium and vitamin D.

To Analyze the Sensitivity of RT-PCR Assays Employing S Gene Target Failure with Whole Genome Sequencing Data during Third Wave by SARS-CoV-2 Omicron Variant

Introduction: Omicron is a highly divergent variant of concern (VOCs) of a severe acute respiratory syndrome SARS-CoV-2. It carries a high number of mutations in its spike protein hence;it is more transmissible in the community by immune evasion mechanisms. Due to mutation within S gene, most Omicron variants have reported S gene target failure (SGTF) with some commercially available PCR kits. Such diagnostic features can be used as markers to screen Omicron. However, Whole Genome Sequencing (WGS) is the only gold standard approach to confirm novel microorganisms at genetically level as similar mutations can also be found in other variants that are circulating at low frequencies worldwide. This Retrospective study is aimed to assess RT-PCR sensitivity in the detection of S gene target failure in comparison with whole genome sequencing to detect variants of Omicron. Methods: We have analysed retrospective data of SARS-CoV-2 positive RT-PCR samples for S gene target failure (SGTF) with TaqPath COVID-19 RT-PCR Combo Kit (ThermoFisher) and combined with sequencing technologies to study the emerged pattern of SARS-CoV-2 variants during third wave at the tertiary care centre, Surat. Results: From the first day of December 2021 till the end of February 2022, a total of 321,803 diagnostic RT-PCR tests for SARS-CoV-2 were performed, of which 20,566 positive cases were reported at our tertiary care centre with an average cumulative positivity of 6.39% over a period of three months. In the month of December 21 samples characterized by the SGTF (70/129) were suggestive of being infected by the Omicron variant and identified as Omicron (B.1.1.529 lineage) when sequence. In the month of January, we analysed a subset of samples (n = 618) with SGTF (24%) and without SGTF (76%) with Ct values Conclusions: During the COVID-19 pandemic, it took almost more than 15 days to diagnose infection and identify pathogen by sequencing technology. In contrast to that molecular assay provided quick identification with the help of SGTF phenomenon within 5 hours of duration. This strategy helps scientists and health policymakers for the quick isolation and identification of clusters. That ultimately results in a decreased transmission of pathogen among the community.

The Role of Quality Control in Targeted Next-generation Sequencing Library Preparation

Next-generation sequencing （NGS） is getting routinely used in the diagnosis of hereditary diseases, such as human cardiomyopathies. Hence. it is of utter importance to secure high quality sequencing data, enabling the identification of disease-relevant mutations or the conclusion of negative test results. During the process of sample preparation, each protocol for target enrichment library preparation has its own requirements for quality control （QC）; however, there is little evi- dence on the actual impact of these guidelines on resulting data quality. In this study, we analyzed the impact of QC during the diverse library preparation steps of Agilent SureSelect XT target enrichment and lllumina sequencing. We quantified the parameters for a cohort of around 600 samples, which include starting amount of DNA, amount of sheared DNA, smallest and largest fragment size of the starting DNA; amount of DNA after the pre-PCR, and smallest and largest fragment size of the resulting DNA; as well as the amount of the final library, the corresponding smallest and largest fragment size, and the number of detected variants. Intriguingly, there is a high tolerance for variations in all QC steps, meaning that within the boundaries proposed in the current study, a considerable variance at each step of QC can be well tolerated without compromising NGS quality.

Identification of 8 Rare Deleterious Variants in ADAMTS13 by Next-generation Sequencing in a Chinese Population with Thrombotic Thrombocytopenic Purpura

Objective Thrombotic thrombocytopenic purpura(TTP)is a rare and fatal disease caused by a severe deficiency in the metalloprotease ADAMTS13 and is characterized by thrombotic microangiopathy.The present study aimed to investigate the genes and variants associated with TTP in a Chinese population.Methods Target sequencing was performed on 220 genes related to complements,coagulation factors,platelets,fibrinolytic,endothelial,inflammatory,and anticoagulation systems in 207 TTP patients and 574 controls.Subsequently,logistic regression analysis was carried out to identify the TTP-associated genes based on the counts of rare deleterious variants in the region of a certain gene.Moreover,the associations between common variants and TTP were also investigated.Results ADAMTS13 was the only TTP-associated gene(OR=3.77;95%CI:1.82–7.81;P=3.6×10^(-4))containing rare deleterious variants in TTP patients.Among these 8 variants,5 novel rare variants that might contribute to TTP were identified,including rs200594025,rs782492477,c.T1928G(p.I643S),c.3336_3361del(p.Q1114Afs*20),and c.3469_3470del(p.A1158Sfs*17).No common variants associated with TTP were identified under the stringent criteria of correction for multiple testing.Conclusion ADAMTS13 is the primary gene related to TTP.The genetic variants associated with the occurrence of TTP were slightly different between the Chinese and European populations.

Application of next-generation sequencing in thalassemia screening:A systematic review and meta-analysis

Objective:To evaluate the value of next-generation sequencing(NGS)in the prevention and management of thalassemia.Methods:A systematic search was performed in eight databases including China Biomedical Literature Database,Chinese National Knowledge Infrastructure,Chinese Scientific Journals Database,Wanfang database,PubMed,EMBASE,Web of Science,and Cochrane Library from the inception to 1 June 2022.Stata 17.0 and Review Manager 5.4 were used for the meta-analysis.Results:Nine studies containing 14794 participants were included in the meta-analysis.Compared with the routine genetic testing(including Gap-PCR and reverse dot blot),NGS had higher detection rates in screening thalassemia(RR 1.22,95%CI 1.13-1.31,P<0.01),particularly for theα-thalassaemia mutation carriers(RR 1.24,95%CI 1.07-1.44,P<0.01).However,no significant difference was found in the screening ofβ-thalassemia(RR 1.10,95%CI 0.99-1.23,P>0.05).Conclusions:Compared with routine genetic testing,NGS had a higher detection rate in general,particularly in the detection ofα-thalassemia.

Next-generation Sequencing of MHC Class Ⅰ Genes Reveals Trans-species Polymorphism in Eutropis multifasciata and Other Species of Scincidae

The genes of the major histocompatibility complex(MHC) encode cell surface proteins that are essential for adaptive immunity. MHC genes show the most prominent genetic diversity in vertebrates,reflecting the adaptation of populations to their evolving environment, population survival and reproduction. In the present study, we used nextgeneration sequencing(NGS) to study the loci polymorphism of exon 3 of the MHC class Ⅰ genes in an ovoviviparous skink, the many-lined sun skink,Eutropis multifasciata and five other species of Scincidae, to quantify genetic variation. In addition,we genotyped the same MHC class Ⅰ genes of E.multifasciata using clone sequencing, to directly compare the effectiveness of both analytical techniques for MHC genotyping. NGS detected 20MHC class Ⅰ alleles in E. multifasciata, and 2 to 15 alleles in the other five Scincidae species. However,clone sequencing detected only 15 of those MHC class Ⅰ alleles in E. multifasciata. In addition, transspecies polymorphism of MHC class Ⅰ genes was studied by constructing a phylogenetic tree using the gene sequences obtained by NGS. Phylogenetic analysis revealed that MHC class I alleles were shared among different species of Scincidae with trans-species polymorphism, and did not exhibit specific genealogical inheritance. These results have important implications for understanding polymorphism interspecies diversity in the MHC genes of Scincidae, and the evolution of the MHC more broadly.

Pulmonary nocardiosis with bloodstream infection diagnosed by metagenomic next-generation sequencing in a kidney transplant recipient:A case report

BACKGROUND Pulmonary nocardiosis is difficult to diagnose by culture and other conventional testing,and is often associated with lethal disseminated infections.This difficulty poses a great challenge to the timeliness and accuracy of clinical detection,especially in susceptible immunosuppressed individuals.Metagenomic nextgeneration sequencing(mNGS)has transformed the conventional diagnosis pattern by providing a rapid and precise method to assess all microorganisms in a sample.CASE SUMMARY A 45-year-old male was hospitalized for cough,chest tightness and fatigue for 3 consecutive days.He had received a kidney transplant 42 d prior to admission.No pathogens were detected at admission.Chest computed tomography showed nodules,streak shadows and fiber lesions in both lung lobes as well as right pleural effusion.Pulmonary tuberculosis with pleural effusion was highly suspected based on the symptoms,imaging and residence in a high tuberculosisburden area.However,anti-tuberculosis treatment was ineffective,showing no improvement in computed tomography imaging.Pleural effusion and blood samples were subsequently sent for mNGS.The results indicated Nocardia farcinica as the major pathogen.After switching to sulphamethoxazole combined with minocycline for antinocardiosis treatment,the patient gradually improved and was finally discharged.CONCLUSION A case of pulmonary nocardiosis with an accompanying bloodstream infection was diagnosed and promptly treated before the dissemination of the infection.This report emphasizes the value of mNGS in the diagnosis of nocardiosis.mNGS may be an effective method for facilitating early diagnosis and prompt treatment in infectious diseases,which overcomes the shortcomings of conventional testing.

Metagenomic next-generation sequencing for pleural effusions induced by viral pleurisy:A case report

BACKGROUND Viral pleurisy is a viral infected disease with exudative pleural effusions.It is one of the causes for pleural effusions.Because of the difficult etiology diagnosis,clinically pleural effusions tend to be misdiagnosed as tuberculous pleurisy or idiopathic pleural effusion.Here,we report a case of pleural effusion secondary to viral pleurisy which is driven by infection with epstein-barr virus.Viral infection was identified by metagenomic next-generation sequencing(mNGS).CASE SUMMARY A 40-year-old male with a history of dermatomyositis,rheumatoid arthritis,and secondary interstitial pneumonia was administered with long-term oral prednisone.He presented with fever and chest pain after exposure to cold,accompanied by generalized sore and weakness,night sweat,occasional cough,and few sputums.The computed tomography scan showed bilateral pleural effusions and atelectasis of the partial right lower lobe was revealed.The pleural fluids were found to be yellow and slightly turbid after pleural catheterization.Thoracoscopy showed fibrous adhesion and auto-pleurodesis.Combining the results in pleural fluid analysis and mNGS,the patient was diagnosed as viral pleuritis.After receiving Aciclovir,the symptoms and signs of the patient were relieved.CONCLUSION Viral infection should be considered in cases of idiopathic pleural effusion unexplained by routine examination.mNGS is helpful for diagnosis.

Molecular methods for colorectal cancer screening:Progress with next-generation sequencing evolution

Currently,colorectal cancer(CRC)represents the third most common malignancy and the second most deadly cancer worldwide,with a higher incidence in developed countries.Like other solid tumors,CRC is a heterogeneous genomic disease in which various alterations,such as point mutations,genomic rearrangements,gene fusions or chromosomal copy number alterations,can contribute to the disease development.However,because of its orderly natural history,easily accessible onset location and high lifetime incidence,CRC is ideally suited for preventive intervention,but the many screening efforts of the last decades have been compromised by performance limitations and low penetrance of the standard screening tools.The advent of next-generation sequencing(NGS)has both facilitated the identification of previously unrecognized CRC features such as its relationship with gut microbial pathogens and revolutionized the speed and throughput of cataloguing CRC-related genomic alterations.Hence,in this review,we summarized the several diagnostic tools used for CRC screening in the past and the present,focusing on recent NGS approaches and their revolutionary role in the identification of novel genomic CRC characteristics,the advancement of understanding the CRC carcinogenesis and the screening of clinically actionable targets for personalized medicine.

Soft tissue tuberculosis detected by next-generation sequencing:A case report and review of literature

BACKGROUND Soft tissue tuberculosis is rare and insidious,with most patients presenting with a localized enlarged mass or swelling,which may be factors associated with delayed diagnosis and treatment.In recent years,next-generation sequencing has rapidly evolved and has been successfully applied to numerous areas of basic and clinical research.A literature search revealed that the use of next-generation sequencing in the diagnosis of soft tissue tuberculosis has been rarely reported.CASE SUMMARY A 44-year-old man presented with recurrent swelling and ulcers on the left thigh.Magnetic resonance imaging suggested a soft tissue abscess.The lesion was surgically removed and tissue biopsy and culture were performed;however,no organism growth was detected.Finally,Mycobacterium tuberculosis was confirmed as the pathogen responsible for infection through next-generation sequencing analysis of the surgical specimen.The patient received a standardized anti-tuberculosis treatment and showed clinical improvement.We also performed a literature review on soft tissue tuberculosis using studies published in the past 10 years.CONCLUSION This case highlights the importance of next-generation sequencing for the early diagnosis of soft tissue tuberculosis,which can provide guidance for clinical treatment and improve prognosis.

Comprehensive next-generation sequencing reveals double primary colorectal carcinoma missed by diagnostic imaging: A case report

BACKGROUND Multiple primary colorectal carcinoma(MPCC)is a rare clinical disease,which is challenging to differentiate from metastatic disease using histopathological methods.Next-generation sequencing(NGS)has been employed to identify multiple primary cancers.CASE SUMMARY This study a rare case of a 63-year-old male patient diagnosed with MPCC by targeted NGS,which was initially missed by radiological evaluation.The patient was found to have two tumors located on the surface of the colorectum which had distinct genomic alterations.Based on wild-type KRAS detected in the unresected tumor,the patient benefited from the epidermal growth factor receptor(EGFR)inhibitor cetuximab treatment,but developed novel mutations including KIF5B-RET fusion,which provides a possible resistance mechanism to anti-EGFR therapy.CONCLUSION Our case highlights the necessity of using genetic testing for primary tumor diagnosis and the application of serial plasma circulating tumor DNA profiling for dynamic disease monitoring.