Identification of sequence polymorphisms in the D-loop region of mitochondrial DNA as valuable biomarkers for salivary gland tumors: an observational study

Abstract

Abstract Background Salivary gland tumor frequency in the head and neck region is quite less and mostly benign. However, pathogenesis is associated with oxidative stress in the mitochondria. Hence, we are aiming to identify single nucleotide polymorphisms (SNP)/single nucleotide variants (SNV) in the mitochondrial DNA D-loop region of salivary gland tumors (SGT). We analyzed 19 biopsied tissue (formalin-fixed paraffin-embedded) tumors, i.e., pleomorphic adenoma-5, mucoepidermoid carcinoma-6, adenoid cystic carcinoma-5, and polymorphous low-grade adenocarcinoma-3. This extracted DNA was amplified to visualize the entire D-loop region of the mitochondrial genome of SGT. Results The three hotspot mutation were noticed at 16,519 (thymine-cytosine) (number = 10), 73 (adenine-guanine) (number = 8), and 195 (thymine-adenine) (number = 4) in the D-loop in salivary gland tumors. We observed novel synonymous mutation in the 195 region of mitochondrial D-loop, which is a novel as per Mitomap (a human mitochondrial genomic database). Conclusions We hypothesized that the biological behavior of SGT is majorly dependent upon the stress level at mitochondria in the D-loop region. SNPs noted in mt-DNA should be noted as a pivotal biomarker for the progression or metastasis of SGT in individuals at risk.

Keywords

• D-loop
• Mitochondria
• Variations
• Salivary gland
• Tumor