Oesophageal cancer is a malignant tumour found in the tissues of the oesophagus. The tumour starts in the mucosa and as it grows deeper into the oesophageal wall, the risk that it might spread to other parts of the body increases. The annual number of cases reported has been on the rise; furthermore, oesophageal cancer is the most difficult form of cancer to treat.
Now, scientists at the Institute of Cancer Research, London, have seemingly discovered the Achilles Heel of this cancer. The team has discovered a genetic weakness in oesophageal cancer cells that makes them particularly sensitive to a drug called ibrutinib, which is already used to treat blood cancer.
The breakthrough was found after the painstaking task of blocking the function of certain genes in cancer cells and then testing their vulnerability to cancer drugs. In total, they assessed 720 key genes and managed to discover Janssen’s Imbruvica was effective at killing cancer cells whilst leaving healthy cells relatively unharmed.
The study appearing in the journal Gut, demonstrated that oesophageal cancer cells with a cancer-causing mutation in a gene called MYC become dependent upon or “addicted” to a second gene, known as BTK. And by blocking the function
of BTK using ibrutinib, the researchers were able to kill oesophageal cancer cells grown in the lab, leaving normal cells relatively unaffected.Researchers are now assessing whether ibrutinib will work in oesophageal cancer patients with MYC mutations in a clinical trial at the Royal Marsden Hospital.
Irish Cancer Society (ICS) head of research Dr Robert O’Connor said. “Each year nearly 400 Irish people are diagnosed with oesophageal cancer (cancer of the pipe which brings food into the stomach), and unfortunately, many patients present late with this disease so treatment can be challenging with only one in five patients (mostly early stage) having durable remission and cure. We look forward to the results of human trials of the proposed treatment which will tell us in a few years if the new approach proposed is a useful new way of treating this form of cancer.”
“Finding which genes cancers are addicted to is an exciting approach for identifying new ways of attacking tumours,” he said. “We can now systematically identify genes which cancer cells need but healthy cells can live without – offering up the potential of precision therapies that have fewer side-effects than conventional treatments.”
Dr Irene Chong, clinician scientist at the ICR and oncologist at the Royal Marsden, concluded, “Our new study has identified a potential Achilles’ heel in some forms of oesophageal cancer, which we believe could be exploited by new treatments. And because there is an existing drug for other forms of cancer which attacks this weakness, we can test out our new approach rapidly in clinical trials.”
The researchers on the study also opened up their findings for scientists around the world so the approach and findings of the study can be replicated to potentially discover new combinations. For Janssen, it could potentially open up a new indication for its drug.
