Mumbai: Researchers from Tata Memorial Centre’s Kharghar centre have identified genetic factors that, for the first time, explain why some tobacco chewers in India develop oral cancer a decade earlier than others.“We come across people who use tobacco, a common cause for oral cancer, for decades and don’t get cancer while there are other users who are diagnosed with cancer early on. Our research provides an answer,” said Dr Pankaj Chaturvedi, director of ACTREC in Kharghar. The genetic findings also explain why some who have never used tobacco or similar carcinogenic substances still get oral cancer.The research, published in ‘eBioMedicine’, part of The Lancet Discovery Science, on Saturday, analysed genetic data from 2,160 cancer patients and 2,325 healthy individuals over a 10-year period. The researchers, led by Dr Rajesh Dikshit and Dr Sharayu Mhatre, identified significant genetic risk areas on chromosomes 5 and 6 (near genes including CLPTM1L-TERT, HLA-DRB1, HLA-DQB1, and CEP43). “A meta-analysis using data from Europe and Taiwan identified novel risk loci near the NOTCH1 gene,” said Dr Dikshit.The team then calculated that tobacco chewers with high genetic susceptibility developed oral cancer a decade earlier than those with low genetic risk. Every year, India records about 1.4 lakh oral cancer cases, with some states having high rates of 33 per 1 lakh population. Lead author Dr Mhatre said that while tobacco use remains the strongest risk factor for buccal mucosa (inner cheek) cancer, a genetic susceptibility component also plays a role. Dr Chaturvedi said the risk of developing oral cancer is 26 times higher among tobacco chewers compared to non-users. He added that genetic susceptibility markers further double the risk among those with a high genetic risk score.However, TMC director Dr Sudeep Gupta emphasised that although genetic susceptibility is important to understand, tobacco chewing remains the single-most preventable cause of oral cancer, with over 80% of cases potentially avoidable through effective tobacco control policies. A press release quoted Dr Siddhartha Kar from Cambridge University as saying, “This landmark study advances our understanding of why oral cancer is so common in India, uncovering uniquely Indian genetic risk factors. By showing how inherited risk interacts with tobacco use, it lays the groundwork for targeted prevention and early detection.”
