Cytomegalovirus (CMV) is a common virus in our community. Most adults will show serological evidence of of previous exposure. CMV can cause severe disease, but generally this is only in newborns or in immunosuppressed patients, such as those people having had a transplant.
In the last few years, it has become clear that CMV can be identified in brain tumour tissue – both in primary gliomas (glioblastoma, astrocytoma, GBM) and also in metastatic tumours (Cobbs et al, Cancer Research, 2002; Taher et al., Translational Oncology, 2014). We don’t really know what the viral particles are doing in brain tumour cells. It is unlikely that the tumours are actually caused by the virus. However, the virus may promote growth of tumour cells.
The presence of the viral particles does provide an opportunity to develop specific treatments however. One overseas trial used an antiviral drug (valganciclovir) in GBM patients and there appeared to be some improvement in outcome.
We have employed a different approach – we have used the viral particles to be the target of immunotherapy. We have conducted this world-leading research over the last few years and our results are very encouraging (Crough et al, 2012; Schuessler et al, 2014). Our trials continue and we hope to be presenting the latest results at international conferences in 2017.
A fascinating new paper has just been published in the journal Neuro-Oncology. Goerig et al (2016) have described a frequent occurrence of CMV-associated encephalopathy (brain inflammation) during radiotherapy for brain tumours (gliomas and metastatic tumours). This has never been looked at before and the frequency of this encephalopathy (it affected in almost half of all patients that had been shown to be positive for CMV before treatment commenced) is astounding. Currently, clinical deterioration during radiotherapy is usually attributed to disease progression or perhaps oedema from the radiotherapy. Now it seems, CMV-encephalopathy could be the culprit.
The results do need to be repeated at other centres and in more patients, but it could have a big impact on treatment regimes in the future. It may also have a significant effect on how we might design our own anti-CMV trials in the future. We are already working on that!!
Prof David Walker is a neurosurgeon and spinal surgeon at BrizBrain & Spine. He has a special clinical interest in brain tumours and is actively involved in conducting research to help find a cure for this disease. Prof Walker is also the Managing Director of the Newro Foundation, a research organisation that conducts research into brain and spine conditions.