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Researchers identify key genetic factors causing oral cancer early among Indian tobacco chewers

Why is this Topic in News?

• Researchers at ACTREC, Tata Memorial Centre, Mumbai have identified key genetic markers responsible for early onset of oral cancer among tobacco chewers in India.
• Individuals with high polygenic risk score (genetic susceptibility) were found to develop oral cancer 10 years earlier compared to those with low risk.
• Study published in eBioMedicine (Lancet Discovery Science) highlights genetic predisposition in addition to lifestyle factors.

What is Oral Cancer?

• Oral cavity cancer is one of the most common and preventable cancers in India, predominantly associated with tobacco chewing.
• It includes cancers occurring in buccal mucosa (inner lining of cheeks) and other oral tissues.
• India reports around 1,41,342 cases, with average age-standardised rate 10.0 per 1,00,000 people, reaching 25–33 per 1,00,000 in some states.

Study Overview

• Conducted as a Genome-Wide Association Study (GWAS) by the Centre for Cancer Epidemiology (CCE), ACTREC.
• Sample compared: 2,160 buccal mucosa cancer cases vs 2,325 controls across different regions.
• Findings revealed genetic risk loci on chromosomes 5 and 6, near genes:
  • CLPTM1L-TERT
  • HLA-DRB1
  • HLA-DQB1
  • CEP43
• Meta-analysis integrating European and Taiwan data identified novel risk loci near NOTCH1 gene.

Key Findings

• Tobacco chewers with high genetic susceptibility showed 24% relative excess cases compared to low-risk individuals.
• Risk of oral cancer is 26 times higher among tobacco chewers than non-users.
• Study indicates immune pathways and calcium-permeable nicotine receptor-related genes play roles in carcinogenesis.
• Highlights need for India-specific genetic data due to variations from European genetic profile.

Significance of Research

• Provides first clear genetic explanation for varied cancer onset among individuals with similar lifestyle habits.
• Supports potential development of early screening tools based on genetic risk profiling.
• Enhances scope for targeted prevention strategies and precision oncology.

Challenges Highlighted

• High burden of oral cancer with late diagnosis common, leading to increased mortality.
• Despite being preventable, tobacco consumption remains widespread, intensifying disease load.

Way Forward

• Integrating genetic screening with public health interventions can enable early diagnosis among high-risk populations.
• Strengthen research for Indian-specific genomic datasets to refine risk assessment.
• Awareness programmes on tobacco hazards along with targeted preventive strategies for susceptible groups.
• Improve early detection infrastructure for reducing late-stage presentation.

Updated – 01 December 2025 ; 07:04 PM IST | News Source: The Hindu