Characterization of the salivary microbiome in patients with pancreatic cancer
- Department of Biology, San Diego State University, San Diego, CA, United States; DOE/OSTI
- Department of Medical Sciences, Harvard University, Boston, MA, United States
- Graduate Program in Biophysical Sciences, University of Chicago, Chicago, IL, United States; Institute for Genomics and Systems Biology, Argonne National Laboratory, Lemont, IL, United States
- Department of Surgery, University of California, San Diego, La Jolla, CA, United States
- Department of Biology, San Diego State University, San Diego, CA, United States; Department of Pediatrics, University of California San Diego School of Medicine, La Jolla, CA, United States
- Department of Biology, San Diego State University, San Diego, CA, United States
Clinical manifestations of pancreatic cancer often do not occur until the cancer has undergone metastasis, resulting in a very low survival rate. In this study, we investigated whether salivary bacterial profiles might provide useful biomarkers for early detection of pancreatic cancer. Using high-throughput sequencing of bacterial small subunit ribosomal RNA (16S rRNA) gene, we characterized the salivary microbiota of patients with pancreatic cancer and compared them to healthy patients and patients with other diseases, including pancreatic disease, non-pancreatic digestive disease/cancer and non-digestive disease/cancer. A total of 146 patients were enrolled at the UCSD Moores Cancer Center where saliva and demographic data were collected from each patient. Of these, we analyzed the salivary microbiome of 108 patients: 8 had been diagnosed with pancreatic cancer, 78 with other diseases and 22 were classified as non-diseased (healthy) controls. Bacterial 16S rRNA sequences were amplified directly from salivary DNA extractions and subjected to high-throughput sequencing (HTS). Several bacterial genera differed in abundance in patients with pancreatic cancer. We found a significantly higher ratio ofLeptotrichiatoPorphyromonasin the saliva of patients with pancreatic cancer than in the saliva of healthy patients or those with other disease (Kruskal–Wallis Test;P< 0.001).Leptotrichiaabundances were confirmed using real-time qPCR withLeptotrichiaspecific primers. Similar to previous studies, we found lower relative abundances ofNeisseriaandAggregatibacterin the saliva of pancreatic cancer patients, though these results were not significant at theP< 0.05 level (K–W Test;P= 0.07 andP= 0.09 respectively). However, the relative abundances of other previously identified bacterial biomarkers, e.g.,Streptococcus mitisandGranulicatella adiacens, were not significantly different in the saliva of pancreatic cancer patients. Overall, this study supports the hypothesis that bacteria abundance profiles in saliva are useful biomarkers for pancreatic cancer though much larger patient studies are needed to verify their predictive utility.
- Research Organization:
- Argonne National Lab (ANL), Lemont, IL (United States)
- Sponsoring Organization:
- Environmental Protection Agency (EPA) STAR Graduate Fellowship; National Institutes of Health (NIH) Public Health Service; USDOE Office of Science (SC)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1628923
- Journal Information:
- PeerJ, Journal Name: PeerJ Vol. 3; ISSN 2167-8359
- Publisher:
- PeerJ Inc.Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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