Scientists discover oral cancer biomarkers associated with patient survival
DUNEDIN, New Zealand/KOLKATA, India: In a recent study, researchers have discovered epigenetic markers that are markedly different in oral cancer tissue compared with the adjacent healthy tissue in patients. This study is one of the first to identify epigenetic markers in oral cancer. Identifying these markers could help detect early signs of cancer and significantly improve patient survival rates.
The study was conducted by researchers from the University of Otago in New Zealand and the Indian Statistical Institute (ISI) in Kolkata. The research team recruited 16 oral cancer patients in India who either smoked or chewed tobacco or had mixed habits, and took samples of their tumours and adjacent tissue. After isolating the DNA in the samples, the researchers discovered regions with altered epigenetic profiles in tumour cells compared with adjacent cells.
Epigenetics can alter gene expression in cancer cells without changes to the DNA sequence and can cause tumour progression. “This phenomenon is relatively new and understudied, particularly in oral cancer. This study is one of the first to identify epigenetic markers in oral cancer, using cutting-edge approaches,” said co-author Dr Aniruddha Chatterjee, Senior Research Fellow and Rutherford Discovery Fellow in the Department of Pathology at the Dunedin School of Medicine at the University of Otago. The findings showed that the arrangement of a certain epigenetic mechanism, called DNA methylation, might be responsible for dictating gene expression and the spread of abnormal cells. “By validating in a larger cancer cohort, we have shown that a subset of these biomarkers is significantly associated with poor prognosis of patients,” Chatterjee said.
The age-adjusted incidence of oral cancer in the world is estimated at four cases per 100,000 people, according to the World Health Organization. This oral disease is more common in men and in older people, and varies considerably by socio-economic condition. According to the 2019 report of "India Against Cancer", of the 300,000 cases of tobacco-associated oral cancer detected globally, 86 per cent are from India. Additionally, late diagnosis and poor prognosis are key problems associated with the high mortality rate of this cancer in developing countries. The research group was surprised to find such broad differences in the oral cancer tissue compared with adjacent healthy tissue in the same patients. “We were also surprised to see that small molecules, called microRNA, were methylated or demethylated in the tumours from smokers or chewers or mixed habits, suggesting that therapeutic intervention might be different in patients depending on the way the tobacco was abused,” said lead author Dr Roshni Roy, professor in the Department of Pathology at the University of Otago.
The study, titled “Genome-wide miRNA methylome analysis in oral cancer: Possible biomarkers associated with patient survival,” was published in the April 2019 issue of Epigenomics.