Personalized therapy for Metastatic Lung Cancer
Treatment Based on EGFR and BRCA1 Gene Mutations Brings Promises
The lungs are a pair of breathing organs found within the chest. Small cell lung cancer is a cancer in which cells grow in a uncontrolled manner in the tissues of the lung. There are two types of lung cancer: one is called non-small cell lung cancer (NSCLC) and the other one, small-cell lung cancer. These two types of cancer are diagnosed based on how they look under a microscope. The first type, NSCLC, grows more slowly than the small-cell lung cancer (SCLC). Both types of cancer behave differently and need different kinds of treatment.
Lung Cancer and Statistics
The estimated number of deaths due to lung cancer is 20,500 in Canada and 160,000 in US. The major risk factor is smoking but other environmental factors, such as air pollution and asbestos, are also involved. Unfortunately, the 2-year survival rate for this cancer is below 20%. For more details see the Canadian Cancer Society web site (www.cancer.ca).
Oncogenes and Tumor Suppressors
Genes that when expressed at high level or when mutated lead cells to become cancerous are called oncogenes. Well-known oncogenes in small-cell-lung cancer are K-ras and EGFR (Epithelial Growth Factor Receptor). In consequence a common treatment for small-cell-lung cancer are drugs, like erlotinib, binding EGFR and inhibiting its activity.
On the other hand, tumor suppressor genes are those protecting cells from becoming cancerous. However, when these genes are mutated, cells are no more protected and become cancerous more easily. A well-know tumor suppressor gene is the BRCA1 gene. Lung cancer patients with high expression of BRCA1 are sensitive to drugs like paclitaxel while patients with low BRCA1 are more sensitive to the cisplatin drug.
Personalized Medicine for Lung Cancer Patients
In the last decade, scientists and oncologists have clearly realized that there will not be one magical cure for cancer and the survival rate of treated cancer patients not only depends on the efficiency of the chemotherapeutic drugs used but also on the types and subtypes of cancer. A subtype of cancer can be defined by different clinical, pathological, genetic and molecular factors.
A recent clinical study directed by Dr Miquel Taron from the Hospital de Terrassa (in Barcelona, Spain) has treated 123 patients from 25 different centers in Spain using a customized approach. Patients with EGFR mutations received an Erlotinib chemotherapeutic treatment and those without EGFR mutations received a chemotherapeutic treatment containing or not cisplatin. The cisplatin treatment was given based on their BRCA1 expression level.
This new study, published in May 2009 in the scientific journal PLoS One, was entitled "Customized treatment in Non-Small-cell Lung Cancer Based on EGFR Mutations and BRCA1 mRNA Expression". (PLoS ONE 4(5):eS133.doi.10.1371/journal.pone.0005133).
More Efficient Treatment for Lung Cancer Patients
With a customized chemotherapy treatment based on EGFR and BRCA1 profile, the Spanish group has been able to obtain a survival rate of 31%, significantly superior than the rate obtained with the standard treatments. Furthermore, they have identified the RAP80 gene as an additional factor influencing the chemotherapy. A treatment targeting RAP80 in addition to EGFR and BRCA1 may improve the efficiency of the customized treatment.
This study not only shows that a more personalized treatment is effective for NSLC patients but gives also hope that personalized treatment will be effective for other types of cancer.
Lung Cancer Tissue
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