Scientists have discovered that experimental drugs developed as treatments of ovarian and breast cancer could be used to treat lung cancer, according to a study published in the journal Oncogene.
Researchers from The Institute of Cancer Research (ICR) in London have revealed that drugs called PARP (poly ADP ribose polymerase) inhibitors could help treat around 50% of non-small-cell lung cancer (NSCLC) tumors.
PARP inhibitors are already used as a treatment for women suffering from breast or ovarian cancer caused by faulty BRCA1 or BRCA2 genes. The inhibitors work by targeting two DNA repair systems at the same time, killing cancer cells while avoiding the healthy cells.
The researchers say that this most recent research shows that PARP inhibitors may work in a similar way with NSCLC tumors.
They explain that half of NSCLC tumors have a fault that blocks one of the ways cells repair errors in DNA. The fault is in a key protein involved in DNA repair called Excision Repair Cross-Complementation group 1 (ERCC1).
Using PARP inhibitors for NSCLC could work by damaging another DNA damage repair system, the researchers say. This could cause secondary damage and kill lung cancer cells, while avoiding damage to healthy tissue.
Dr. Chris Lord, a scientist at the ICR, says:
"Lung cancer is hard to treat and unfortunately has very poor survival, so there is an urgent need to find new treatments. Our research opens up an exciting new route, by showing how we could repurpose drugs originally designed for use against other forms of cancer."
He adds: "We now need to build on this promising early research by testing PARP inhibitors against lung cancer in clinical trials to confirm whether they can benefit patients."
According to the American Cancer Society, around 85-90% of lung cancers are non-small cell lung cancers, and it is the second most common cancer in both men and women worldwide.
Survival rates of NSCLC remain low. At stage one of the cancer, when it has not yet spread to the lymph nodes or other organs, there is an estimated five-year survival rate of 49%.
"Lung cancer is proven to be one of the hardest cancers to study and survival rates remain poor," says Dr. Harpal Kumar, chief executive of Cancer Research UK, which funded the study.
"We're making substantial investments in lung cancer research to discover better ways to diagnose and treat the disease. Our hope is that studies like this will lead to more effective treatments for lung cancer patients and ultimately save more lives."
The study authors say that the next steps for this research will be to conduct clinical trials for the use of PARP inhibitors in appropriately selected patients.