Molecular features of gastroenteropancreatic neuroendocrine carcinoma: A comparative analysis with lung neuroendocrine carcinoma and digestive adenocarcinomas

Objective: There is an ongoing debate about whether the management of gastroenteropancreatic(GEP)neuroendocrine carcinoma(NEC) should follow the guidelines of small-cell lung cancer(SCLC). We aim to identify the genetic differences of GEPNEC and its counterpart.Methods: We recruited GEPNEC patients as the main cohort, with lung NEC and digestive adenocarcinomas as comparative cohorts. All patients undergone next-generation sequencing(NGS). Different gene alterations were compared and analyzed between GEPNEC and lung NEC(LNEC), GEPNEC and adenocarcinoma to yield the remarkable genes.Results: We recruited 257 patients, including 99 GEPNEC, 57 LNEC, and 101 digestive adenocarcinomas.Among the mutations, KRAS, RB1, TERT, IL7R, and CTNNB1 were found to have different gene alterations between GEPNEC and LNEC samples. Specific genes for each site were revealed: gastric NEC(TERT amplification),colorectal NEC(KRAS mutation), and bile tract NEC(ARID1A mutation). The gene disparities between small-cell NEC(SCNEC) and large-cell NEC(LCNEC) were KEAP1 and CDH1. Digestive adenocarcinoma was also compared with GEPNEC and suggested RB1, APC, and KRAS as significant genes. The TP53/RB1 mutation pattern was associated with first-line effectiveness. Putative targetable genes and biomarkers in GEPNEC were identified in22.2% of the patients, and they had longer progression-free survival(PFS) upon targetable treatment [12.5 months vs. 3.0 months, HR=0.40(0.21-0.75), P=0.006].Conclusions: This work demonstrated striking gene distinctions in GEPNEC compared with LNEC and adenocarcinoma and their clinical utility.

The extracellular secretion of miR-1825 wrapped by exosomes increases CLEC5A expression:A potential oncogenic mechanism in ovarian cancer

Background:Ovarian cancer(OC)is a leading cause of gynecological cancer-linked deaths worldwide.Exosomal miR-1825 and its target gene C-type lectin domain family 5 member A(CLEC5A)are associated with tumorigenesis in cancers that was further probed.Methods:Exosomal miR-1825 expression in exosomes and its impact on overall survival(OS)prediction were determined using Gene Expression Omnibus(GEO)and The Cancer Genome Atlas(TCGA)data.Target genes of miR-1825 were searched in five prediction databases and prognostically significant differentially expressed genes were identified.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were carried out.The ability of CLEC5A to predict OS was evaluated using univariate and multivariate Cox regression analyses and Kaplan-Meier curves.The CLEC5A expression pattern in OC was validated using immunohistochemistry.The CIBERSORT algorithm was used to compare the immune cell landscape,and the results were validated in a GEO cohort.Finally,the predicted half maximal inhibitory concentration(IC50)values for five commonly used chemotherapy agents were also compared.Results:MiR-1825 level was higher in exosomes derived from OC cells and served as a tumor suppressor.The CLEC5A gene was found to be a target of miR-1825,the upregulation of which was correlated with a poor prognosis.M2 macrophage infiltration was significantly enhanced in the CLEC5A high expression group,while T follicular helper cell infiltration was reduced in it.While the predicted IC50 for cisplatin and doxorubicin was higher in the CLEC5A high expression group,that of docetaxel,gemcitabine,and paclitaxel was lower.Conclusion:MiR-1825,a promising OC biomarker,may promote OC progression by increasing CLEC5A expression via exosome-mediated efflux from tumor cells.

Successful treatment of refractory lung adenocarcinoma harboring a germline BRCA2 mutation with olaparib:A case report

BACKGROUND In recent years,targeted therapy and immunotherapy have become important treatment strategies for patients with non-small cell lung cancer(NSCLC).However,the clinical evidence for successful off-label use of targeted drugs for patients with NSCLC following progression on multiple lines of treatment is still lacking.CASE SUMMARY We describe a 62-year-old male patient with a right lung adenocarcinoma who harbored an EGFR exon 19 deletion mutation.He received gefitinib combined with six cycles of vinorelbine,cisplatin,and recombinant human endostatin as the first-line therapy.Then gefitinib was administered in combination with recombinant human endostatin as maintenance therapy,resulting in a progression-free survival(PFS)of 14 mo.Chemoradiotherapy was added following progression(enlarged brain metastases)on maintenance treatment.Unfortunately,the brain lesions were highly refractory and progressed again after 15 mo,at which time next-generation sequencing(NGS)of 1021 cancer-related genes was performed using peripheral blood to identify potential actionable mutations.NGS revealed that the patient harbored a BRCA2 germline mutation,the EGFR exon 19 deletion mutation disappeared,and no additional targetable genetic variant was detected.Therefore,the patient received olaparib combined with gefitinib and recombinant human endostatin,with a rapid and long-lasting clinical response(PFS=13.5 mo).CONCLUSION This is a rare case of lung adenocarcinoma in a patient with a BRCA2 germline mutation who had long-term benefit from olaparib combination treatment,suggesting that NGS-based genetic testing may render the possibility of long-term survival in NSCLC patients after disease progression.

Integrated circulating tumor DNA and T cell repertoire predict radiotherapeutic response and outcome in non-small cell lung cancer patients with brain metastasis

Dear editor,The scarcity of routinemetastatic biopsies or resection limits the finding of biomarkers of diagnosis and prognosis in patients with brain metastases.Derived from necrosis,apoptosis,and secretion of tumor cells,circulating tumor DNA(ctDNA)is widely distributed in various body fluids,including peripheral blood and cerebrospinal fluid(CSF),as an alternative biomarker for tumor-associated analysis[1].Fortunately,genomic alterations of blood ctDNA and CSF ctDNA have been proven as prognostic markers in non-small cell lung cancer(NSCLC)patients with brain metastasis[2,3].

Clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA from breast cancer patients in China

Background:TP53 mutations are common in breast cancer.There is currently no large-scale cohort study to investigate the TP53 landscape in breast cancer patients from China.The predictive value of TP53 mutations for the efficacy of human epidermal growth factor receptor 2(HER2)-targeted therapy in breast cancer remains controversial.In the present study,we aimed to analyze the clinical spectrum and prognostic value of TP53 mutations in circulating tumor DNA(ctDNA)from breast cancer patients in China.Methods:We retrospectively analyzed the clinical data and TP53 mutation features in ctDNA samples from 804 patients withmetastatic breast cancer.TP53 mutations were detected by target region capture-based next-generation sequencing.The relationship between TP53 mutation status and disease-free survival(DFS)was analyzed in 444 patientswithmetastatic breast cancer.Moreover,the relationship between TP53 mutation status and progression-free survival(PFS)was analyzed in 55 HER2-positive patients treated with first-line trastuzumab-based therapy.Kaplan-Meier analysis was performed to estimate the survival curves of the different subgroups,and the log-rank test was used to compare the curves.A Cox regression model was used to estimate multivariable-adjusted hazard ratios and their 95%confidence intervals(CIs)associated with the DFS and PFS.Results:Among the 804 investigated patients,431(53.6%)patients harbored TP53 mutations.TP53 mutations were differentially distributed among different molecular subtypes of breast cancer(P<0.05).Patients with TP53 mutations had a shorter DFS than those with wild-type TP53(hazard ratio=1.32,95%CI=1.09-1.61,P=0.005).TP53 mutations in exons 5-8 were associated with worse outcome(hazard ratio=1.50,95%CI=1.11-2.03,P=0.009).However,TP53 mutation status was not significantly associated with PFS in HER2-positive patients who received firstline trastuzumab-based therapy(P=0.966).Interestingly,in the taxane combination group,patients with TP53 mutations exhibited longer PFS than those without TP53 mutations(hazard ratio=0.08,95%CI=0.02-0.30,P<0.001).However,in the nontaxane combination group,patients with TP53 mutations displayed shorter PFS than those with wild-type TP53(hazard ratio=4.84,95%CI=1.60-14.66,P=0.005).Conclusions:TP53 mutations in exons 5-8 may be an independent prognostic marker for short DFS in patients with metastatic breast cancer.TP53 mutations had opposite effects on trastuzumab-treated patients treated with and without taxanes.

Mutational characteristics determined using circulating tumor DNA analysis in triple-negative breast cancer patients with distant metastasis

Dear editor,Breast cancer has been considered as the most common malignancy and the leading cause of death in women worldwide[1].Triple-negative breast cancer(TNBC)accounts for 10%-20%of breast cancers,which are characterized by the absence of estrogen receptor(ER),progesterone receptor(PR),and amplification of human epidermal growth factor receptor 2(HER2)[2].TNBC is well known for its rapid progressiveness,high rate of distant organ recurrence,and poor prognosis.Metastasis remains the major cause of death for patients with TNBCs.Up to date,the only direct treatment for metastatic TNBCs is chemotherapy,which has been challenged by tumor heterogeneity and drug resistance.Lack of effective targeted therapy for metastatic TNBCs impels researchers to focus on discovering potentially actionable targets through mutational profiling.

Evolution of tumor microenvironment in colorectal liver metastases under treatment stress

Dear editor,The tumor microenvironment(TME)heavily impacts disease biology and may influence responses to systemic treatments,and thereby,affects patients’prognosis.In our previous study,we found that immune features could predict prognosis and guide the therapy choices for stage I-III colon cancer[1,2].Increasing evidence shows that therapyinduced TME changes can promote tumor progression,metastasis,and the development of resistance[3,4].However,the TME dynamics in colorectal liver metastases(CRLM)under treatment are still incompletely clear.

The molecular tumor burden index as a response evaluation criterion in breast cancer

Circulating tumor DNA(ctDNA)is a potential biomarker of prognosis and therapeutic response.We conducted this study to explore the role of the molecular tumor burden index(mTBI)in ctDNA as a therapeutic response and prognostic biomarker in a larger cohort prospective phase III randomized multicenter study.We collected 291 plasma samples from 125 metastatic breast cancer patients from the CAMELLIA study(NCT01917279).Target-capture deep sequencing of 1021 genes was performed to detect somatic variants in ctDNA from the plasma samples.The pretreatment mTBI value was correlated with tumor burden(P=0.025).Patients with high-level pretreatment mTBI had shorter overall survival than patients with low-level pretreatment mTBI,and the median overall survival was 40.9 months and 68.4 months,respectively(P=0.011).Patients with mTBI decrease to less than 0.02%at the first tumor evaluation had longer progression-free survival and overall survival(P<0.001 and P=0.007,respectively).The mTBI has good sensitivity to identify complete response/partial response and progressive disease based on computed tomography scans(88.5%and 87.5%,respectively).The patients classified as molecular responders had longer progression-free survival and overall survival than the nonmolecular responders in the overall cohort(P<0.001 and P=0.036,respectively),as well as in the cohort in which computed tomography scans were defined as representing stable disease(P=0.027 and P=0.015,respectively).The mTBI in ctDNA detected in liquid biopsies is a potential biomarker of therapeutic response and prognosis in patients with metastatic breast cancer.

Preferable background filtering for next-generation sequencing analysis in non-small cell lung cancer:pericarcinomatous tissues or peripheral blood lymphocytes?

Dear editor,Lung cancer is the leading cause of cancer-related death worldwide,with the predominant pathological type being non-small cell lung cancer(NSCLC)[1,2].Next-gener-ation sequencing(NGS)analysis is increasingly used to help clinicians select appropriate target therapies,such as epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKIs)for EGFR-mutant patients[3].Both pericarcinomatous tissues and peripheral blood lymphocytes are widely used as normal control for NGS analysis.However,whether pericarcinomatous tissue is suitable for background filtering in mutation analysis remains controversial.According to the whole-genome sequencing data from The Cancer Genome Atlas(TCGA)database,there were some genomic variations in peri-carcinomatous tissue from NSCLC patients,but no driver gene mutation was detected[4,5].Therefore,deep sequencing of pericarcinomatous and tumor tissues is necessary to confirm whether pericarcinomatous tissue harbors low-frequency mutations.

Genomic characterization reveals distinctmutation landscapes and therapeutic implications in neuroendocrine carcinomas of the gastrointestinal tract

Background:Neuroendocrine carcinomas of the gastrointestinal tract(GINECs)remain a disease of grim prognosis with limited therapeutic options.Their molecular characteristics are still undefined.This study aimed to explore the underlying genetic basis and heterogeneity of GI-NECs.Methods:Comprehensive genomic analysis using whole-exome sequencing was performed on 143 formalin-fixed,paraffin-embedded samples of surgically resected GI-NEC with a thorough histological evaluation.Mutational signatures,somatic mutations,and copy number aberrations were analyzed and compared across anatomic locations and histological subtypes.Survival analysis was conducted to identify the independent factors.Results:In total,143GI-NECswere examined:the stomach,87 cases(60.8%);the esophagus,29 cases(20.3%);the colorectum,20 cases(14.0%);and the small intestine,7 cases(4.9%).Eighty-three(58.0%)and 60(42.0%)cases were subclassified into small cell and large cell subtypes,respectively.GI-NECs showed distinct genetic alterations from their lung counterparts and non-neuroendocrine carcinomas in the same locations.Obvious heterogeneity of mutational signatures,somatic mutations,and copy number variations was revealed across anatomic locations rather than histological subtypes.Except for tumor protein p53(TP53)and retinoblastoma 1(RB1),the most frequently mutated genes in the stomach,esophagus,colorectum,and small intestine were low-density lipoprotein receptor-related protein 1B(LRP1B),notch receptor 1(NOTCH1),adenomatosis polyposis coli(APC),catenin beta 1(CTNNB1),respectively.Mutations in the WNT-β-catenin,NOTCH and erythroblastic leukemia viral oncogene B(ERBB)pathwayswere prevalently identified in gastric,esophageal,and colorectalNECs,respectively.Importantly,104(72.7%)GI-NECs harbored putative clinically relevant alterations,and non-gastric location and RB1 bi-allelic inactivation with copy number alterations were identified as two independent poor prognostic factors.Furthermore,we found that tumor cells in GI-NECs first gain clonal mutations in TP53,RB1,NOTCH1 and APC,followed by subsequent wholegenome doubling(WGD)and post-WGD clonal mutations in LRP1B,CUB and Sushi multiple domains 3(CSMD3),FAT tumor suppressor homolog 4(FAT4)and erb-b2 receptor tyrosine kinase 4(ERBB4),and finally develop subclonal mutations.Conclusions:GI-NECs harbor distinct genomic landscapes and demonstrate significant genetic heterogeneity across different anatomic locations.Moreover,potentially actionable alterations and prognostic factors were revealed for GI-NECs.