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E-mail address: [email protected] (K. Ankita).
every 100,000 population and are estimated to be high. Regardless of the advantage of early detection of oral cancers, with the available diagnostic aids, most oral cancers are diagnosed late, leading to poor treatment outcomes . This fact emphasizes on the prompt significance of patient education and the need to improve the ability of a clinician to recognize early malignant and premalignant changes in the oral cavity .
Since the advent of the ‘omics’ technologies, a plethora of new tools to understand complex biological systems have become available. Promising research is progressing in the field of biomarkers which can aid us in the early diagnosis of OSCC. A cancer biomarker for a specific tumor type can provide vital information needed to successfully treat cancer [4,5]. The ultimate
Please cite this article in press as: Ankita K, et al. Assessment of salivary endothelin-1 in patients with leukoplakia, submucous fibrosis, oral cancer and healthy individuals – a comparative study. J Stomatol Oral Maxillofac Surg (2019), https://doi.org/10.1016/ j.jormas.2019.02.024
goal in the discovery of biomarkers is to increase the survivability of cancer through improved diagnostics and treatment . One such field is the salivary biomarkers. The salivary biomarkers are classified as metabolomics, proteomic and transcriptomic markers . Studying the proteome, i.e. the protein complement of the genome (proteomics), has been proven to be effective in the analysis of protein expression and protein modification in cells/ tissues/organisms. The systematic and simultaneous analysis of proteins expressed by a certain cell type or tissue has become possible with the advent of proteomics. The protein abundances, post-translational modifications (PTMs) and the study of protein structure and interactions can be characterized by these technol-ogies.
One such proteomic biomarker is endothelin. Endothelin is a peptide which is composed of 21 SCH-772984 with 2 disulphide bonds between amino acids 1 and 15 and 3 and 11. A resultant big endothelin (with 39 amino acids) is formed by cleavage of the pre-pro-endothelin precursor, by means of specific endopeptidases. Conversion of big endothelin to endothelin is then carried out by the action of an endothelin-converting enzyme (ECE) . Endo-thelins comprise a group of three small peptides: ET-1, ET-2 (with similar structure of ET-1) and ET-3 [8,9]. ET-1 activates ETAR which largely contributes to tumour growth and progression, inducing proliferation of cell, survival, angiogenesis and metastatic spread, indicating that ETAR antagonism might improve cancer treatment. ET-1, by acting via ETBR, modulates different stages of neovascu-larization. ET-1 can also modulate tumour angiogenesis indirectly, through induction of vascular endothelial growth factor (VEGF). Activation of ETAR by ET-1 induces VEGF production by increasing the levels of hypoxia-inducible-factor 1a (HIF 1a) .
Endothelin plays a significant role in tumorigenesis and saliva being an important diagnostic tool we planned a study to assess the salivary endothelin levels in patients with oral squamous cell carcinoma and oral potentially malignant disorders. Also ours was the first study to evaluate the levels of salivary ET-1 in patients with submucous fibrosis.
2. Materials and methods
Patients visiting the Outpatient department of Oral Medicine and Radiology between the months of February 2018 to September 2018 were included in the study. Clinically and histopathologically confirmed cases of oral leukoplakia (OL), sub mucous fibrosis (SMF), oral cancer (OSCC) comprised the study group. Age and sex matched healthy individuals were taken as controls. A sample size of 60 subjects was divided into 4 groups; 15 in each group (OL, SMF, OSCC and normal healthy controls). Patients with chronic systemic diseases, medically compromised, on corticosteroids or immunosuppressant therapy and patients with conditions affect-ing the quality and quantity of saliva were excluded from the study. The study was approved by the institutional ethical committee number (UECHT/2016-2018/PGDT/OR02). A written informed consent in English/ vernacular language was obtained from the subjects participating in the study upon fulfilling the inclusion criteria
Demographic distribution of subjects within the study group.
2.1. Saliva collection and preparation
Individuals were asked to refrain from eating, drinking, smoking, and oral hygiene procedures for at least 1 hour prior to saliva collection. They were asked to rinse their mouth with water; 5 mL of unstimulated whole saliva sample was collected from each subject using salivary spitting method into sterile uricol containers. The saliva samples were then centrifuged at 5000 rpm for 20 min. at +4degree C to remove cell debris and the supernatants were stored at 80 8C for further analysis. Salivary endothelin 1 levels were quantified using Human endothelin-1 Solid Phase Sandwich ELISA kit (Krishgen biosystems, India).