An extremely precise profile of meningiomas, which account for 30% of all brain tumours, has been created. The results are published in the Nature Genetics journal. The first experimental tests with a new drug.
Meningioma is one of the most common brain tumours (it accounts for about 30% of all brain cancers) and is not easy to combat. As its name implies it develops in the meninges, the membranes surrounding the outer part of the brain, and can vary greatly in terms of histology, i.e. the structure of the cancerous cells, and in its threat to life, depending on which blood vessels and neighbouring organs are incorporated into the neoplastic mass.
In order to clearly define the specific features of the tumours in each patient (and therefore the possible treatments), the surgically removed part is usually examined whenever possible. This analysis means that meningiomas can be divided into three subclasses. However, this is no more than 70% accurate and of course is not the best way to establish treatment.
A breakthrough, however, could come thanks to a major genetic study carried out by researchers at the University of California, San Francisco, and the University of Hong Kong, published in the scientific journal Nature Genetics. Oncologists examined 565 tumours from the same number of patients, using almost every genetic weapon available to them and created a much more accurate profile than is currently possible.
In particular, they focused their attention on tumoral RNA fragments (RNA is one of the key molecules for 'putting into practice' the information contained in DNA). The researchers also examined those parts of the DNA of cancer cells that are altered by chemical 'groups' formed by one carbon atom and three hydrogen atoms (methyls).
Experimental treatment with abemaciclib
Good molecular characterisation is the first step towards more specific therapies and the new elements discovered by the researchers meant that meningiomas could be classified into three subtypes different from the usual ones, on the basis of clearly distinguishable genetic features.
One of the cells of the 'new' subtypes showed a marked ability to duplicate themselves (something that explains how easily the tumour reforms, despite treatment). The researchers decided to experiment with a drug – abemaciclib – to combat this hypermitotic sub-type. Abemaciclib is already being studied as an inhibitor of rapid cell replication and has recently been authorised by US and European health authorities for certain forms of breast cancer with a high risk of recurrence.
When administered to animals, abemaciclib slowed the progression of metastatic meningioma and the same was seen in a small group of patients who had no response to any other treatment. Symptoms improved and lesion volume decreased.
Researchers have also conducted numerous tests on meningioma cell cultures and organoids (fragments of the brain, with associated blood vessels, created in the laboratory from tumour cells), also with encouraging results.
Awaiting new tests
In short, there are all the conditions to proceed fairly quickly with testing on a larger number of patients, in the hope that results will be confirmed and that a truly effective therapeutic tool will soon be available for sufferers.
It is also hoped that the genetic classification will help further progress with all forms of meningioma, creating a better understanding of the different types of the disease.