Cancer: genome sequencing throws light on origins
One genetic mutationoccurs on average for every 15 cigarettes that a typical lung cancer patientsmokes, according to a study reported in Natureby a research team at the Wellcome Trust Sanger Institute in the UK.
In a full genetic analysis of the genomes of cancer patients, they studied a lung cancer patient who had accumulated about 23,000 DNA mutations in his lung cells that were linked with exposure to the toxins in cigarette smoke. The study involved sequencing the entire genome of a lung cancer cell 60 times in order to ensure that all of the smallest mutations were identified in the patient and then comparing the genome sequence with that of a healthy cell taken from the patient.
In the same study, they found a patient with malignant melanoma who had acquired 30,000 specific genetic mutations known to be associated with exposure to sunlight. In this case, and using the same procedure, the researchers were able to show that the malignant cells contained changes resulting from exposure to ultraviolet light.
Team leader Prof Mike Stratton said that, with these genome sequences, the team had been able to explore deep into the past of each tumour, uncovering the imprints of the mutagens on DNA, which occurred years before the tumour had become apparent.
Published: 01 Mar 2010