The role of astrocytes in secondary brain tumours
Brain metastasis, the secondary growth of malignant cells within the brain, are more common than primary brain tumours and the incidence has been reported to be on the rise. They typically originate from lung, breast and melanoma tumours where cells break away (metastasise) and ultimately travel to the brain through the bloodstream. It has been estimated that up to 40% of people with these cancers may develop secondary brain tumours.
Although more effective drugs to treat and cure these cancer types are being developed, not all can cross the blood-brain barrier to enter into the brain. Therefore, once a secondary tumour is established the range of therapies that can be used in their treatment is significantly diminished.
Despite the fact that metastasis to the brain poses a significant unmet clinical problem, with afflicted patients carrying significant morbidity, our knowledge of how metastatic cells manage to interact with the local tissue environment of the brain remains limited. This problem has been discussed by researchers at the Spanish National Cancer Research Centre in their recent article.
According to recent studies on the molecular mechanisms responsible for metastatic spread to the brain and the subsequent growth, this review highlights the role of astrocytes as the primary type of brain cells which the cancer cells encounter and interact with during the development of secondary tumour growth within the brain. The astrocytes detect the metastatic cancer cells and become more permissive, allowing the secondary tumours to embed and grow. Therefore, developing mechanisms by which this could be interrupted may be an approach to minimise the growth of secondary brain tumours.
Understanding the impact of astrocytes, as one of the key host cell types in the development of secondary brain tumours, may serve not only to understand the functional importance of the microenvironment in the development of this secondary tumour growth in the brain, but also to explore additional implications related to biomarkers and innovative therapies.
A recent study also identified genetic subtypes of secondary tumours which influences the best therapy that should be used in order to get the best clinical outcome.
Research at our Centre of Excellence in the University of Portsmouth is investigating how these tumours cross into the brain and also how they become embedded and grow. By understanding the ways in which secondary tumours flourish in the brain, we will be able to identify potential mechanisms by which we can treat them optimally.