Effectiveness of lung cancer treatment may depend on ethnicity:
According to new research, genetic differences could explain why particular ethnic groups respond better to chemotherapy treatment for lung cancer. A team lead by researchers from the University of Texas Southwestern Medical Centre said that the findings could be useful in tailoring cancer treatments to individual patients.
The study, published in Public Library of Science Medicine, looked at a protein called epidermal growth factor receptor (EGFR), known to be involved in several types of cancer. More than half of lung cancers are caused when excessive amounts of EGFR are produced and several drugs that interfere with EGFR are used in chemotherapy.
Researchers focused on three specific mutations in the gene that codes for EGFR, which can lead to the increased production of this protein. They compared the genes of 250 healthy people of various ethnicities with 556 samples from benign and cancerous lung tumours. They found that amongst those who were not affected, people from East Asia were less likely to carry any of the mutations when compared to healthy people of European, African or Mexican descent.
However, of those affected by lung cancer, it was East Asians who were more likely to have one of the mutations that can lead to the excessive production of EGFR. Dr Gazdar, one of the authors of the paper, said that the findings could explain why East Asians are known to respond better than other ethnic groups to a type of chemotherapy that inhibits EGFR activity. He added that this type of cancer analysis could explain the differences in the incidence of lung cancer amongst ethnic groups, as well potentially leading to the matching of specific treatments to the patient.
Meanwhile, a team based at the University of California has shown that genetic variations can also affect response to other types of lung cancer drugs. David Gandara and colleagues studied 156 Japanese and US patients with advanced non-small cell lung cancer, being treated with paclitaxel and carboplatin. They found that half of the Japanese group survived for one year, compared to just over a third of the US group.
The scientists found that differences in four genes could explain the different treatment outcomes. A patient’s response to the chemotherapy drugs depends on their genetic make-up, rather than their ethnicity per se, the study shows. Gandara presented the findings at the recent annual meeting of the American Society of Clinical Oncology.
Sources:
Genetic variation-Lung cancer drugs work better in the Japanese than in the Americans: RxPG News: 3 June 2007
Gene analysis might explain ethnic differences in sensitivity to chemotherapy in lung cancer: EurekAlert: 23/4/07
Polymorphisms, Mutations, and Amplification of the EGFR Gene in Non-Small Cell Lung Cancers: PloS Medicine: 24 April 2007