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B. Harmon
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P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)
- Event: WCLC 2015
- Type: Poster
- Track: Biology, Pathology, and Molecular Testing
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.04-060 - Analysis of Lung Microbiome From Patients Undergoing Bronchoscopy (ID 1072)
09:30 - 09:30 | Author(s): B. Harmon
- Abstract
Background:
Recent studies have demonstrated diversity in the lung microbiomes of chronic obstructive pulmonary disease and healthy individuals. Lung microbial communities may not just serve as a predictor of cancer development, but also as a target of pharmacological cancer prevention strategies. We sought to characterize the lung microbiome diversity within patients with lung cancer for comparison to those without lung cancer.
Methods:
Signed informed consent was obtained from patients ages 18 years and older that underwent a bronchoscopy during the course of clinical evaluation at one of two cancer centers. A bronchial lavage was collected for research purposes after routine bronchoscopic procedures were completed. The lavage sample was collected in a sterile collection container and immediately placed on dry ice. Subsequently, samples were diluted 1:1, incubated with dithiothreitol to aid in mucus dissolution, and then mechanically homogenized. DNA was extracted and 515F/806R 16S rRNA primers used to amplify Variable Region 4. Amplicons were sequenced using the Illumina MiSeq. Sequences were clustered into operational taxonomic units (OTUs) using QIIME’s open reference OTU picking workflow, and taxonomy was assigned to OTUs by classification against the Greengenes database using the RDP Classifier. Microbial communities were compared using phylogenetic beta diversity metrics based on 16S rRNA reads. Statistical significance of diversity between samples was determined by comparing the UniFrac distances between pairs of samples using parametric and non-parametric Monte Carlo-based t-tests. Differences in alpha diversity were tested using a t-test comparing the distributions of diversity values across the sample types.
Results:
None of the patients undergoing a research-related bronchial lavage experienced a significant adverse event from the procedure. There were seven lung cancer patients with a median age of 56.0 years (range 45-75). Of these, six were current/former smokers with an average of 32.5 pack-years. All seven lung cancer patients were Caucasian with five using prescription inhalers and none on recent antibiotics. Five patients had adenocarcinoma and one each of squamous cell carcinoma and small cell lung cancer. There were six non-lung cancer patients with a median age of 57.5 years (range 39-68). Of these, three were current/former smokers with an average of 40 pack-years. All six non-lung cancer patients were Caucasian with three using prescription inhalers and one recently taking antibiotics. Analyses of the microbiota present in lung samples show the presence of multiple bacterial taxonomic groups in each sample, however, the phylogenetic diversity of the bacterial community is low compared to other body sites. Fusobacteria represented a significant portion of the bacterial community of lavage samples. Not surprisingly, the community composition of these samples is most similar to human oral communities, however, a portion of these communities is unlike communities from other characterized human body sites and we are still actively investigating these differences.
Conclusion:
Microbiota associated with lung cancer have not been well-characterized or associated with treatment and outcome. Our analyses suggest that bacterial communities may play an important role in cancer development and present an opportunity to better characterize these communities and their components. Updated results will be presented at WCLC.
