Targeted cancer treatments, based on genetic profiling results, could soon become a reality. A team lead by researchers at the Dana-Farber Cancer Institute, in the US, has found that only lung tumours with a particular gene mutation are likely to respond to treatment with the drug gefitinib. The work is published in the early online edition of the journal Science. Another study, carried out by researchers at Duke University in Durham, North Carolina, shows that genetic profiling can help predict how breast cancer will progress in different patients. The findings, published in the Proceedings of the National Academy of Sciences, could help doctors decide how best to treat patients, say the team.
The Dana-Farber scientists looked at non small cell lung cancer tumours (NSCLC), the most common form of lung cancer, from 58 Japanese and 61 US patients. They also recorded how well the patients had responded to gefitinib (trade name Iressa). The researchers tested the tumours for mutations in the EGFR gene, which makes a cell growth protein involved in NSCLC, called epidermal growth factor receptor. Gefitinib is designed to block the action of this protein, but has not been as effective as expected, based on preliminary trials carried out in Japan.
The new study found that only lung cancer tumours with mutations in the EGFR gene are likely to respond to gefitinib. This could explain its low success rate in other countries - the scientists found that 26 per cent of the Japanese patients had EGFR mutations, compared to only two per cent of the US patients. 'This is a huge deal', said team member Matthew Myerson, adding that it confirms that 'targeted therapy is going to work for major common tumours and not just rare ones'.
In the breast cancer study, researchers used 'gene chips' to look at the activity of thousands of genes in tumour samples from 158 women. They found that certain patterns of gene activity could predict a patient's prognosis, such as whether the cancer would return after treatment. The technique could help doctors decide how aggressively to treat a person's cancer, and which therapies might be most successful, says team leader Mike West. 'This study is the validation of the concept that this kind of molecular genetics information will have an impact on clinical decision making', he said.