New framework for monitoring the development of oral cancer, progression, recurrence -
Each year approximately 22,000 Americans are diagnosed with oral cancer. The five-year survival rate of 40% in the United States is one of the lowest of the major cancers, and it has not improved over the last 40 years. More people die each year in the United States of oral cancer than melanoma, cervical, or ovarian cancer. Worldwide, the incidence of oral cancer is increasing, especially among young people and women, with an estimated 350,000 -. 400,000 new cases diagnosed each year
"The risk factors, tobacco, and major alcohol alone can not explain the changes in incidence, because the oral cancer also occurs frequently in patients without history of tobacco or alcohol exposure, "said Dr. Brian Schmidt, professor of oral surgery and maxillofacial surgery and director of Bluestone Center for clinical research at the NYU College of Dentistry (NYUCD).
changes in the microbial community are generally associated with dental diseases such as periodontal disease, which is most likely a polymicrobial disease characterized by the development of some disease organisms, and chronic periodontitis has been reported to be a risk factor for precancerous lesions and oral cancers.
"We know that other cancers, including the gall bladder, colon, lung and prostate cancer, have been associated for specific bacterial infections, so we hypothesized that changes in the composition of the normal microbiome of the oral cavity may be promoters or causes of oral cancer, "said Dr. Albertson.
Drs. Schmidt and Albertson and cancers of the team and contoured anatomically matched contralateral normal tissues of the same patient by sequencing the 16S rDNA hypervariable region amplicons. The results of the team, "Changes in the abundance of oral microbiota associated with oral cancer," published online in the journal PLOS ONE (June 2014), begin to develop a framework for operation of the oral microbiome for oral monitor cancer development, progression and recurrence.
in the cancer samples both a discovery (n = 5), and a subsequent cohort confirmation (n = 10), the abundance of Firmicutes (especially Streptococcus) and actinobacteria (especially Rothia) was decreased significantly compared to normal samples from the same patient contralateral. significant decreases in abundance of these branches were observed for pre-cancers, but not when comparing samples from contralateral sites (tongue and floor of the mouth) healthy individuals. using the differences in the abundance of genera Actinomyces, Rothia, and Streptococcus Fusobacterium, the team was able to separate most cancer samples from pre-cancer and normal samples.
"The oral cavity offers a relatively unique opportunity to screen people at risk for cancer (oral), because the lesions can be seen, and as we have seen, the passage in the microbiome cancerous lesions and precancerous compared to anatomically matched clinically normal tissues of the same individual can be detected in non-invasive swab samples collected. "Dr. Schmidt said.
Noninvasive sampling the microbiome oral lesions and corresponding normal tissue opens the possibility not only to detect changes associated with cancer at some point of time, but the relative stability of adult oral microbiome also offers the possibility to monitor changes in the bacterial communities over time.
"Here, we observed changes in the microbiome, which in future larger studies, can be confirmed as a potential biomarker of oral cancers or pre-cancers, and may even have a usefulness to discriminate patients with lymph node metastases, "says Dr. Albertson." in addition, there are other challenges in the clinical management of oral cancers that would benefit from better diagnostic tools. "
patients of oral cancer are also at risk of second primary and recurrence of cancer. the microbiome can provide signatures that can be used as a biomarker for monitoring of field changes associated with the high rate of secondary cancers and primary oral recurrences. the the team also noted the ability to modulate the oral microbiome medically for the treatment of pre-cancers of the mouth and damaged fields (field cancerization).
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