Researchers have, for the first time, identified a new group of growth factor receptors that signal to brain tumors, which brings treatment of neurofibromatosis type 2 (NF2) one step closer to a nonsurgical therapeutic option.
One in 25,000 people worldwide is affected by NF2, which is a condition where the loss of the tumor suppressor merlin results in multiple tumors in the brain and nervous system. Patients may experience 20 to 30 tumors at any one time. Such numbers often lead to hearing loss, disability, and eventually death. Currently, the only effective therapy is repeated invasive surgery or radiotherapy aimed at one tumor at a time. However, these are not likely to eradicate all the tumors at once. NF2 can affect any family, regardless of past history, through gene mutation. There is no cure.
The study found that the new group of growth factor receptors are overexpressed and activated in certain brain tumors. The study also identified the mechanism that causes this activity and show that, by interfering with activation, tumor cells can be corrected.
Such growth factors are known to play a role in the development of other cancers, but this is the first time that the link has been made to cancer tumors in the brain and nervous system. The breakthrough is crucial to developing nonsurgical therapies for NF2. Currently, drugs that target these growth factor receptors in other cancers are available. The research team has shown that there is scope to adapt such drugs to treat NF2.
The research was led by C. Oliver Hanemann, MD, FRCP, of Plymouth University Peninsula Schools of Medicine and Dentistry, United Kingdom, and published in Oncogene (2013; doi:10.1038/onc.2012.587). He said, “At present the only treatment available to NF2 sufferers is repeated surgery to remove tumors. This is only partially effective, because in some cases tumors are in areas where it is impossible to reach with surgery, and because eradicating a tumor from a part of the brain or nervous system does not mean that another one will not grow in its place. Chemotherapy is not an option, because in most cases NF2 tumors are slow growing–it is their sheer number that causes risk to the patient.
“Our study in Oncogene offers real hope to patients, because it identifies how the growth of NF2 tumors works and shows that existing drugs could be modified to help stop and even reverse the rate of tumor growth. This is good news for patients for two reasons: it shows that there could be a valid alternative to surgery; and because the answer may be the adaptation of existing drugs, therapies could be developed relatively quickly because the process of clinical trials and drug registration has already taken place. Also the mechanism causing tumors in NF2 is also causing many spontaneous brain cancers and is found in other cancers. So what we found has potential relevance for other cancers.”