September 14, 2012
Studies offer ‘panoramic view’ of lung cancer
Lung cancer causes more deaths than any other form of cancer. About 1.6 million people worldwide are diagnosed with the disease each year, with fewer than 20% still alive five years later. Now a trio of genome-sequencing studies published this week1–3 is laying the groundwork for more effective personalized treatment of lung cancers, in which patients are matched with therapies that best suit the particular genetic characteristics of their tumours. Two of the latest studies profiled the genomes of tissue samples from 178 patients with lung squamous cell carcinomas1 and 183 with lung adenocarcinomas2, the largest genomic studies so far performed for these diseases. A third study carried out more in-depth analyses of 17 lung tumours to compare the genomes of smokers and patients who had never smoked3.
...The studies reveal new categories of mutations and also show a striking difference between lung cancer in smokers and non-smokers, with smokers’ tumours exhibiting several times the number of mutations as well as different kinds of mutations. Non-smokers were likely to have mutations in genes such as EGFR and ALK, which can already be specifically targeted with existing drugs. Smokers were particularly likely to have damage in genes involved in DNA repair as well as other characteristic mutations. “These genomes are battle-scarred by carcinogen exposure,” says Govindan. In addition, the patterns of mutations found in lung squamous cell carcinoma more closely resemble those seen in squamous cell carcinomas of the head and neck than those in other lung cancers. That finding adds further weight to the idea that classifying tumours by their molecular profiles, rather than their sites of origin, will be more effective in picking the right drugs to treat them. Perhaps, for instance, a drug approved for treating breast cancer could be tried in a lung cancer if both carry similar mutations. And mutations implicated in other cancers did show up in the lung cancers.
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