Researchers have found that there may be a link between the number of cigarettes a person smokes and the number of cancer-causing genetic mutations they have.
When a team from Roche’s biotechnology unit Genentech in California compared a lung cancer patient’s tumour with healthy tissue, they found as many as 50,000 mutations in the two samples.
Zemin Zhang, part of the team, said: “Fifty thousand is a huge number. No one has ever reported such a high number.”
The patient in question smoked an average of 25 cigarettes each day for 15 years, creating a ratio of one genetic mutation for every three cigarettes smoked.
Because the number of mutations was so high, the team completed extra checks and tried to find anything unusual about the patient. But Mr Zhang concluded: “There is nothing unusual about this sample.”
The researchers made their discoveries using technology to look at entire genomes, rather than single genes linked to cancer. They also found that areas of the genomes that make proteins were less likely to mutate, which was important for cell survival.
However, this has only been tested on the one patient. “Obviously, we’d love to have multiple fully sequenced genomes in multiple tumors,” Mr Zhang said.
The results of the study have been published in the Nature journal.
Click here to see the Nature article here