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Open Access Highly Accessed Research article

Comparison of oral microbiota in tumor and non-tumor tissues of patients with oral squamous cell carcinoma

Smruti Pushalkar1, Xiaojie Ji12, Yihong Li1, Cherry Estilo3, Ramanathan Yegnanarayana4, Bhuvanesh Singh4, Xin Li1 and Deepak Saxena1*

Author Affiliations

1 Department of Basic Sciences and Craniofacial Biology, New York University College of Dentistry, 345 E, 24th Street, Room 921B, New York, NY, 10010, USA

2 Department of Chemical and Biological Sciences, Polytechnic Institute of NYU, New York, NY, USA

3 Dental Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA

4 Laboratory of Epithelial Cancer Biology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA

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BMC Microbiology 2012, 12:144  doi:10.1186/1471-2180-12-144

Published: 20 July 2012



Bacterial infections have been linked to malignancies due to their ability to induce chronic inflammation. We investigated the association of oral bacteria in oral squamous cell carcinoma (OSCC/tumor) tissues and compared with adjacent non-tumor mucosa sampled 5 cm distant from the same patient (nā€‰=ā€‰10). By using culture-independent 16S rRNA approaches, denaturing gradient gel electrophoresis (DGGE) and cloning and sequencing, we assessed the total bacterial diversity in these clinical samples.


DGGE fingerprints showed variations in the band intensity profiles within non-tumor and tumor tissues of the same patient and among the two groups. The clonal analysis indicated that from a total of 1200 sequences characterized, 80 bacterial species/phylotypes were detected representing six phyla, Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, Actinobacteria and uncultivated TM7 in non-tumor and tumor libraries. In combined library, 12 classes, 16 order, 26 families and 40 genera were observed. Bacterial species, Streptococcus sp. oral taxon 058, Peptostreptococcus stomatis, Streptococcus salivarius, Streptococcus gordonii, Gemella haemolysans, Gemella morbillorum, Johnsonella ignava and Streptococcus parasanguinis I were highly associated with tumor site where as Granulicatella adiacens was prevalent at non-tumor site. Streptococcus intermedius was present in 70% of both non-tumor and tumor sites.


The underlying changes in the bacterial diversity in the oral mucosal tissues from non-tumor and tumor sites of OSCC subjects indicated a shift in bacterial colonization. These most prevalent or unique bacterial species/phylotypes present in tumor tissues may be associated with OSCC and needs to be further investigated with a larger sample size.

Microbial diversity; Oral squamous cell carcinoma; Microbiota; Tumor; Non-tumor