RESUMO
Appropriate management requires timely and accurate confirmation of non-small cell lung cancer (NSCLC) recurrence in patients who have had curative-intent surgical resection. We assessed the association between circulating tumor DNA (ctDNA) identified using amplicon sequencing and evidence of recurrence on CT surveillance. A prospective cohort study of NSCLC patients with early-stage disease undergoing curative-intent resection was conducted. Surveillance was performed post-operatively at pre-defined intervals with both liquid biopsy and chest CT imaging. Amplicon panel next-generation sequencing was performed on DNA and RNA from tumor tissue and on plasma cell-free DNA for tumor-informed ctDNA detection. Resected tumors from 78 NSCLC patients were analyzed. Alterations were detected on the DNA assay for 65 tumors and only on the RNA assay for 4 tumors. Of the 65 patients with alterations detected on the tumor DNA assay, 29 completed post-operative liquid biopsy testing. Four of those 29 patients had evidence of recurrence on imaging, of whom two had biopsy confirmation of recurrence and detectable ctDNA at the 12-month follow-up. Molecular confirmation of NSCLC recurrence can be provided through amplicon sequencing of plasma cell-free DNA in cases with imaging evidence of recurrence. Invasive tissue diagnosis may be avoidable in patients with ctDNA confirmation of recurrence that is suspected based on imaging. Further study of ctDNA assessment technologies in the setting of suspected recurrence is necessary to inform post-operative lung cancer surveillance guidelines.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , DNA Tumoral Circulante , Neoplasias Pulmonares , Recidiva Local de Neoplasia , Humanos , Neoplasias Pulmonares/cirurgia , Neoplasias Pulmonares/patologia , Biópsia Líquida/métodos , Feminino , Masculino , Idoso , Pessoa de Meia-Idade , Carcinoma Pulmonar de Células não Pequenas/cirurgia , DNA Tumoral Circulante/sangue , Estudos Prospectivos , Idoso de 80 Anos ou maisRESUMO
OBJECTIVE: Biomarkers reflecting real-time response to therapy and recurrence are lacking. We assessed the clinical value of detecting cell-free circulating tumor DNA (ctDNA) mutations in endometrial cancer (EC) and ovarian cancer (OC) patients. METHODS: EC/OC patients undergoing primary surgery were consented for tissue banking and 2-year serial blood draws. Tumor tissue DNA and plasma ctDNA underwent next generation sequencing using a targeted gene panel to identify somatic mutations. RESULTS: Of 44 patients (24 EC, 17 OC, 2 synchronous endometrial and ovarian carcinomas [SEOC] and 1 endocervical adenocarcinoma [EA]) at least one somatic mutation was identified in tumor tissue in 40 (91%, 20/24 EC, all OC/SEOC/EA), and in preoperative plasma ctDNA in 12 (27%) patients (6/24 [25%] EC and 6/17 [35%] OC). Detection of preoperative ctDNA mutations was associated with advanced stage, higher preoperative CA125, and disease recurrence. In 5/12 (42%) patients with preoperative ctDNA mutations, examination/imaging suggested clinical stage I however final pathology revealed stage II/III. In 11 patients where serial timepoints were assessed during treatment for ctDNA and CA125, ctDNA clearance preceded normalization of CA125. Thirteen patients developed recurrent disease (4 EC, 8 OC, 1 EA); 8 in whom ctDNA mutations were detected postoperatively, and 4 followed through time of recurrence with ctDNA mutations identified 2-5 months prior to clinical/radiologic/biomarker progression in 3. CONCLUSION: ctDNA can reflect larger tumor volume/metastases, treatment response and recurrence in EC and OC. Careful patient selection is critical to direct resources to patients most likely to benefit, considering disease burden and risk group.
RESUMO
The plant microbiome has been recently recognized as a plant phenotype to help in the food security of the future population. However, global plant microbiome datasets are insufficient to be used effectively for breeding this new generation of crop plants. We surveyed the diversity and temporal composition of bacterial and fungal communities in the root and rhizosphere of Brassica napus, the world's second largest oilseed crop, weekly in eight diverse lines at one site and every three weeks in sixteen lines, at three sites in 2016 and 2017 in the Canadian Prairies. We sequenced the bacterial 16S ribosomal RNA gene generating a total of 127.7 million reads and the fungal internal transcribed spacer (ITS) region generating 113.4 million reads. 14,944 unique fungal amplicon sequence variants (ASV) were detected, with an average of 43 ASVs per root and 105 ASVs per rhizosphere sample. We detected 10,882 unique bacterial ASVs with an average of 249 ASVs per sample. Temporal, site-to-site, and line-driven variability were key determinants of microbial community structure. This dataset is a valuable resource to systematically extract information on the belowground microbiome of diverse B. napus lines in different environments, at different times in the growing season, in order to adapt effective varieties for sustainable crop production systems.
RESUMO
Modifying the rhizosphere microbiome through targeted plant breeding is key to harnessing positive plant-microbial interrelationships in cropping agroecosystems. Here, we examine the composition of rhizosphere bacterial communities of diverse Brassica napus genotypes to identify: (1) taxa that preferentially associate with genotypes, (2) core bacterial microbiota associated with B. napus, (3) heritable alpha diversity measures at flowering and whole growing season, and (4) correlation between microbial and plant genetic distance among canola genotypes at different growth stages. Our aim is to identify and describe signature microbiota with potential positive benefits that could be integrated in B. napus breeding and management strategies. Rhizosphere soils of 16 diverse genotypes sampled weekly over a 10-week period at single location as well as at three time points at two additional locations were analyzed using 16S rRNA gene amplicon sequencing. The B. napus rhizosphere microbiome was characterized by diverse bacterial communities with 32 named bacterial phyla. The most abundant phyla were Proteobacteria, Actinobacteria, and Acidobacteria. Overall microbial and plant genetic distances were highly correlated (R = 0.65). Alpha diversity heritability estimates were between 0.16 and 0.41 when evaluated across growth stage and between 0.24 and 0.59 at flowering. Compared with a reference B. napus genotype, a total of 81 genera were significantly more abundant and 71 were significantly less abundant in at least one B. napus genotype out of the total 558 bacterial genera. Most differentially abundant genera were Proteobacteria and Actinobacteria followed by Bacteroidetes and Firmicutes. Here, we also show that B. napus genotypes select an overall core bacterial microbiome with growth-stage-related patterns as to how taxa joined the core membership. In addition, we report that sets of B. napus core taxa were consistent across our three sites and 2 years. Both differential abundance and core analysis implicate numerous bacteria that have been reported to have beneficial effects on plant growth including disease suppression, antifungal properties, and plant growth promotion. Using a multi-site year, temporally intensive field sampling approach, we showed that small plant genetic differences cause predictable changes in canola microbiome and are potential target for direct and indirect selection within breeding programs.