Smoking is a major cause of lung cancer, but it is not the only factor. An increasing number of people who have never smoked are still developing this disease. Recent research has highlighted the role of a rare genetic mutation known as T790M in the EGFR gene. This mutation, found in some individuals from birth, is linked to a significantly higher risk of developing bronchial cancer. According to Time, individuals who carry this mutation have a 25 times greater risk of developing lung cancer than those who do not, regardless of their smoking history. For non-smokers specifically, the risk is even higher—60 times greater compared to non-smokers without the mutation. Researchers describe this mutation as one of the most powerful genetic risk factors for cancer identified to date. The T790M mutation was first identified in a European family in 2005, but its impact was difficult to assess due to its rarity. To better understand its role, researchers turned to the genetic data of 10 million individuals from the company 23andMe, which allows users to consent to their data being used for research. Among these, 3.37 million had also reported whether they had been diagnosed with lung cancer. Jaclyn LoPiccolo, a researcher at the Dana-Farber Cancer Institute, explained that without such a large dataset, it would have been impossible to determine how common the mutation is or how strongly it increases cancer risk. The study found that approximately 1 in 15,000 people in the United States carry this mutation. The EGFR gene is involved in cell growth and division, and mutations in this gene are among the key drivers of lung cancer. However, the T790M variant is not itself a direct cause of cancer. Instead, researchers believe it makes individuals more susceptible to developing cancer if another mutation in the same gene occurs later in life. Targeted therapies have been developed to treat cancers driven by these other EGFR mutations, but the presence of T790M may influence how these treatments work. Experts are now considering whether individuals who carry the T790M mutation—along with other high-risk groups, such as smokers and former smokers over 50—should undergo regular lung cancer screening. Nadia Litterman, director of the Susan Wojcicki Foundation, suggests that early detection through screening could improve outcomes if cancer is found at an earlier, more treatable stage. Another question is whether individuals should undergo genetic testing to determine if they carry this mutation. As research continues, these decisions will likely depend on further studies and guidelines from medical professionals.