Salivary Genomics, Transcriptomics and Proteomics: The Emerging Concept of the Oral Ecosystem and their Use in the Early Diagnosis of Cancer and other Diseases

Abstract

Abstract:There is an increasingly growing interest world-wide for the genomics, transcriptomics and proteomics of saliva and the oral cavity, since they provide a non-invasive source of unprecedently rich genetic information. The complexity of oral systems biology goes much beyond the human genome, transcriptome and proteome revealed by oral mucosal cells, gingival crevicular fluid, and saliva, and includes the complexity of the oral microbiota, the symbiotic assembly of bacterial, fungal and other microbial flora in the oral cavity. In our review we summarize the recent information on oral genomics, transcriptomics and proteomics, of both human and microbial origin. We also give an introduction and practical advice on sample collection, handling and storage for analysis. Finally, we show the usefulness of salivary and oral genomics in early diagnosis of cancer, as well as in uncovering other systemic diseases, infections and oral disorders. We close the review by highlighting a number of possible exploratory pathways in this emerging, hot research field.

Salivary Diagnostics, Current Reality and Future Prospects

“…On the other hand, initial oral carcinomas are not visible and cannot be diagnosed and treated on time. The salivary proteomecan also be used for tumor detection [54].…”

“…In the future, a global proteomic profile of saliva with methods newly developed for proteome analysis is likely to result in other peptide sequences candidates for detection with high sensitivity [62,54].…”

“…The salivary genome consists of DNAs representing the individual's genome and the oral microbiota. The quality and yield of DNA that can be obtained from saliva is relatively good compared to blood and urine, which can be used for genotyping, amplification or sequencing [54], and can be stored for a long time without significant degradation [77].Thus, the salivary DNA is an analyte suitable for diagnosis but limited to reflect the presence or absence of specific genes or alterations in the sequences (mutations) and also cannot provide information about upregulation and downregulation of gene expression.…”

Salivary Diagnostics in Oral Cancer

“…Salivary RNA provides information on the transcription rates of the host genes and those of oral microbiota. Salivary proteins represent genetic information and help to understand the translational regulation of the host body and the oral microbiota (Fabian et al, 2008). In addition, saliva is also useful in detection of other markers such as cell cycle markers (p16, p53 etc), growth factors (Epidermal growth factor, transforming growth factor etc), cell surface markers, oxidant and antioxidants among others.…”

Salivary Metabolomics and Oral Carcinogenesis

“…Salivary RNA provides information on the transcription rates of the host genes and those of oral microbiota. Salivary proteins represent genetic information and help to understand the translational regulation of the host body and the oral microbiota [23] . In addition, saliva is also useful in detection of range of potential markers that includes nonorganic compounds, proteins, cell cycle markers (p16, p53 etc), growth factors (Epidermal growth factor, transforming growth factor etc), cell surface markers, DNA, mRNA, microRNA, oxidant and antioxidants among others [24] .…”