Gene Expression Predicts Brain Tumor Growth Revolutionizing Cancer Treatment

Gene expression tests can be a accurate method to predict the best treatment for cancer patients based on which genes are turned on and off in their tumors.

Based on patterns of gene expression, or which genes are turned on and off, in brain tumors, researchers have developed a highly precise method to predict which treatment would work best for cancer patients. Based on the results of the novel gene expression test, it was found that just 1 in 5 patients with low-grade cancers (those less likely to regrow) may require radiation, while about 2 in 5 patients with higher-grade tumors may benefit from radiation-free treatment.

This study was conducted by researchers at UC San Francisco and Northwestern Medicine, in collaboration with 10 other medical centers, and published in Nature Medicine ().

Gene Expression Test Tracks Tumor Growth Transforming Cancer Therapeutics

Doctors often prescribe radiation along with surgery to treat a brain tumor called meningioma that originates in the protective membranes surrounding the brain. But side effects from radiation can be serious, including memory loss and cognitive decline, so it’s important to know which patients really need it.

Brain Tumor
Brain tumors are the abnormal growth of brain cells that may be benign or metastatic. Brain tumors account for about 2.4% of all the tumor diagnosesandare most challenging due to their critically delicate location.

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Unlike other brain tumors, meningiomas occur most often in female, Black, and elderly patients.

“There’s been a lot of controversy in the field in terms of who should receive radiotherapy and who shouldn't,” said David Raleigh, MD, PhD, a radiation oncologist in the UCSF Brain Tumor Center and a senior author of the study, along with Stephen Magill, MD, PhD, assistant professor of neurological surgery at Northwestern University Feinberg School of Medicine.

“Our biomarker takes the guessing game out of this and shows us which patients are likely to benefit from radiotherapy and which may get toxicity and possibly no benefit from radiation.”

Quiz on Brain Tumor
Brain tumor is a group of cells with abnormal growth in the brain. A primary brain tumor indicates the tumor that starts in the brain. A secondary tumor originates elsewhere in the body and then spreads to the ...

Because meningiomas grow slowly, a patient may be unaware of their tumor until they start to experience neurological symptoms like numbness, vision loss, or personality changes. There are no pharmaceutical treatments, so doctors rely on surgery to remove the tumor and radiation to prevent it from growing back. Doctors treat these tumors based on guidance from the World Health Organization, which stages them according to severity.

Pathologists currently classify meningiomas by looking at them under a microscope for features that indicate whether they may grow back, a system that is very good but not perfect. Patients with Grade 1 tumors don’t usually receive radiation treatment if their tumors can be removed completely during surgery.

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Yet approximately 20% of the time, the tumors recur. Those with Grade 2 and 3 tumors, which are much more aggressive and more likely to grow back after surgery, are often treated with radiation after surgery. It has been unclear how many of these patients, particularly those with Grade 2 tumors, actually need radiation treatment.

Raleigh, along with Magill and lead author William Chen, MD, decided to look at classifying tumors according to which of their genes are turned on and off, thereby offering clues to how aggressive they might be.

Gene Expression Test May Help Minimize Radiation Therapy in Cancer Patients

“Gene-expression tests like this, which analyze a small number of genes at a time, are widely available for breast, prostate, and some other cancers, and they've proven to be a very accurate and inexpensive alternative to other types of tests,” said Chen.

Morbidity and Mortality of Meningioma Resection Increases With Age
Surgery outcomes for meningioma, a tumor that arises from the meninges, the membranes that surround your brain and spinal cord were assessed.

Raleigh and Chen and their multidisciplinary team suspected that gene expression could more accurately point out the patients who would be helped by radiotherapy. Using samples from 1,856 meningioma patients at 12 medical centers in the U.S., Europe and Hong Kong, Raleigh’s team came up with a set of 34 genes whose gene expression patterns had the potential to predict whether a tumor would return.

One-fifth of the Grade 1 tumors – the same number that grow back after surgery – expressed the patterns that Raleigh’s team found could predict a tumor’s regrowth. This fraction of patients may benefit from radiation. The researchers also found that two-fifths of patients with Grade 2 and 3 tumors did not have a recurrence, and this, too, could be predicted by the tumor’s gene expression.

“When to proceed with additional surgery, radiotherapy or simply to observe a small residual meningioma is not always clear,” said Magill. “This test adds information that can let us tailor our surgical and radiation approach to provide the best outcome for each patient and maximize both quality and quantity of life.”

The team’s next step is to test the approach in two clinical trials currently being developed.

Reference:

Targeted gene expression profiling predicts meningioma outcomes and radiotherapy responses - (https://www.nature.com/articles/s41591-023-02586-z)

Source-Eurekalert