Role of bacteria in oral carcinogenesis

Abstract

Oral cancer appears to be increasing in incidence, and mortality has hardly improved over the past 25 years. Better understanding of the etiopathogenesis should lead to more accurate and earlier diagnosis and more effective treatments with fewer adverse effects. Despite increasing interest in the possible relationships between bacteria and the different stages of cancer development, the association of bacteria with cancer of the oral cavity has yet to be adequately examined. Different bacteria have been proposed to induce carcinogenesis, either through induction of chronic inflammation or by interference, either directly or indirectly, with eukaryotic cell cycle and signaling pathways or by metabolism of potentially carcinogenic substances like acetaldehyde, causing mutagenesis. This review presents the possible carcinogenesis pathway involved in bacterial carcinogenesis, commonly implicated bacteria in oral carcinogenesis and their role in cancer therapeutics as well.

Polymicrobial interactions of Candida albicans and its role in oral carcinogenesis

“…Integrins have been recognised as the largest family of cell adhesion molecules that consist of multiple combinations of α‐ and β‐subunits . Proteins synthesised by microorganisms, such as proteases from C albicans and Bcl‐2 family proteins from bacteria, have been shown to induce alteration of integrins in epithelial cells . The α1‐subunit of integrins that preferentially binds to collagen IV, and α3‐subunit that functions as a receptor for laminins, have been reported to change during interaction with the proteins of microorganisms .…”

“…28 Proteins synthesised by microorganisms, such as proteases from C albicans and Bcl-2 family proteins from bacteria, have been shown to induce alteration of integrins in epithelial cells. 3 The α1-subunit of integrins that preferentially binds to collagen IV, and α3-subunit that functions as a receptor for laminins, have been reported to change during interaction with the proteins of microorganisms. 27 Subsequent trigger of a spectrum of signals involved in the process of growth and proliferation may also promote oral carcinogenesis in a paracrine fashion.…”

“…With estimation of oral cancer incidences at approximately 275 000 cases, two‐thirds of these are reported in developing countries . The risk factors that lead to oral squamous cell carcinoma (OSCC) include tobacco smoking, heavy alcohol consumption, poor oral hygiene, unhealthy diets and microbial infection …”

“…2 The risk factors that lead to oral squamous cell carcinoma (OSCC) include tobacco smoking, heavy alcohol consumption, poor oral hygiene, unhealthy diets and microbial infection. 3 Microbial infections by yeast, bacteria and viruses appear to have a causal role in oral cancer. 1,3 Candida spp has been reported to be the most frequent fungal microbiome (mycobiome) isolated from the oral cavity, followed by Cladosporium, Aureobasidium, Saccharomycetales, Aspergillus, Fusarium and Cryptococcus.…”

“…3 Microbial infections by yeast, bacteria and viruses appear to have a causal role in oral cancer. 1,3 Candida spp has been reported to be the most frequent fungal microbiome (mycobiome) isolated from the oral cavity, followed by Cladosporium, Aureobasidium, Saccharomycetales, Aspergillus, Fusarium and Cryptococcus. 4 Candida spp may reflect a secondary infection of a pre-existing altered epithelium when linked with dysplasia.…”