Saliva diagnostics: emerging techniques and biomarkers for salivaomics in cancer detection

ABSTRACT

Introduction

The pursuit of easy-to-use, non-invasive and inexpensive diagnostics is an urgent task for clinicians and scientists. Saliva is an important component of body fluid with regular changes of contents under various pathophysiological conditions, and the biomarkers identified from saliva shows high application potentials and values in disease diagnostics. This review introduces the latest developments in saliva research, with an emphasis on the detection and application of salivary biomarkers in cancer detection.

Areas covered

Detection of disease-specific biomarkers in saliva samples by existing salivaomic methods can be used to diagnose various human pathological conditions and was introduced in details. This review also covers the saliva collection methods, the analytical techniques as well as the corresponding commercial products, with an aim to describe an holistic process for saliva-based diagnostics.

Expert opinion

Saliva, as a non-invasive and collectable body fluid, can reflect the pathophysiological changes of the human body to a certain extent. Identification of reliable saliva biomarkers can provide a convenient way for cancer detection in clinical applications.

KEYWORDS:

• Saliva
• salivaomics
• biomarker detection
• cancer diagnostics

Article highlights

• ‘Salivaomics’ was proposed based on the rapid development of people’s understanding on various omics components in saliva, and can be classified into salivary genome, transcriptome, proteome, metabolome and microbiome.

• Several types of salivary biomarkers (genes, RNAs, proteins, metabolites, etc.) can be used or have great potentials to be applied to clinical cancer diagnosis and prognosis.

• Saliva collection methods, the traditional analytical techniques and the state-of-the-art biosensors for saliva biomarker detection, as well as the corresponding commercial products were discussed in details.

• Characteristic salivary biomarkers as revealed by the most recent studies for different cancer types, i.e. oral cancer, pancreatic cancer, lung cancer, breast cancer and gastric cancer, are specified in this article.

• A combination of different types of salivary biomarkers shows improved accuracy in discriminating cancer patients from healthy controls; while a number of reported salivary biomarkers remain to be confirmed in larger prospective studies.

Declaration of Interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

The authors acknowledge funding from the National Natural Science Foundation of China (81804154), the Shenzhen High-Level Hospital Construction Fund (4001020), the Shenzhen Science and Technology Innovation Committee Funds (JCYJ20190812171807146), and the Fundamental Research Funds for the Central Universities (JQN2022026).