A Review on Salivary Genomics and Proteomics Biomarkers in Oral Cancer

Abstract

Oral cancer has emerged as an alarming public health problem with increasing incidence and mortality rates all over the world. Therefore, the implementation of newer screening and early detection approaches are of utmost importance which could reduce the morbidity and mortality associated with this disease. Sensitive and specific biomarkers for oral cancer are likely to be most effective for screening, diagnosis, staging and follow-up for this dreaded malignancy. Unlike other deep cancers, oral cancer is located in oral cavity. Hence, the direct contact between saliva and oral cancer lesion makes the measurement of tumor markers in saliva an attractive alternative to serum and tissue testing. The DNA, RNA and protein molecules derived from the living cancer cells can be conveniently obtained from saliva. Thus, salivary biomarkers, a non-invasive alternative to serum and tissue-based biomarkers may be an effective modality for early diagnosis, prognostication and monitoring post therapy status. In the current post-genomic era, various technologies provide opportunities for high-throughput approaches to genomics and proteomics; which have been used to evaluate altered expressions of gene and protein targets in saliva of oral cancer patients. The emerging field of salivary biomarkers has great potentials to prove its clinical significance to combat oral cancer. Hence, we have reviewed importance of several salivary genomics and proteomics biomarkers for oral cancer.

Diagnosing oral squamous cell carcinoma using salivary biomarkers

“…16 The major ingredient of saliva is water approximately 99% and remaining percentage belongs to organic as well as inorganic components; in where the inorganic components mostly consist of weak and strong ions including Na+, Ca 2+ , Cl -, (HPO2)3, Mg 2+ , HCO3 and NH3. The organic compo-nents composed of body secretion products like putrefaction products; lipids, and more than 400 types of protein out of which glandular origin proteins (alpha-amylase, cystatin, histatin, lactoferrin, mucin, lysozymes, and proline-rich proteins), plasma derivatives (secretory immunoglobulin A, albumin) and transferrin are very important.…”

“…The transformation rate of precancerous lesion to cancer is about 0 to 20% within 1 -30 years depending on the variety of lesions and follows a sequence of histopathological levels. 16 Although having advancement in surgery, radiation therapy and chemotherapy, there is no remarkable variation in the 5 years-survival rate of oral cancer. Last several years, the survival rate is about 50% worldwide with the reason for late diagnosis, poor response of tumor to chemotherapy and radiation therapy; as well as insufficient biomarkers for early diagnosis and post-therapeutic monitoring.…”

Evaluation of the Role of Salivary Transcriptome as a Diagnostic Aid in Oral Precancer (Homogeneous Leukoplakia) and Oral Cancer

“…Hence, saliva reflects the body in health and disease. 5 The stages that conclude in oral carcinogenesis display histopathologic changes from mild-to-moderate hyperplasia, to severe dysplasia followed by carcinoma in situ and finally precipitating as invasive squamous cell carcinoma. It is a process accompanied by genetic mutations and expression changes of many genes at a molecular level that leads to uncontrolled cellular growth.…”

“…Protein-based biomarkers include a group of biomarkers consisting of cytokines, fibroblast growth factor, cyfra 21-1, cancer antigen-125, tissue polypeptide antigen, endothelium, matrix metalloproteinases, glutathione transferase, and superoxide dismutase. 5 The RNA-based biomarkers are the recently discovered biomarkers, currently the topic of research, including messenger RNAs and micro RNAs. The current topic of research focuses on the use of saliva as a mode of diagnostic tool for early detection of OSCC.…”

Activated Salivary MMP-2 - A Potential Breast Cancer Marker

“…A review on salivary proteomics and genomics has been reported [28]. In chronic periodontitis the role of MMP-2 and 9 has been observed [29]. It has also been reported that salivary protein factors are elevated in breast cancer patients [26].…”