Uveal melanoma – or melanoma of the eye – is a rare form of cancer affecting 7.6 million Aussies. The disease is particularly deadly and has a 50 per cent chance of metastasising – or spreading from the eye.
Metastases of uveal melanoma have been recorded up to 20 years after the primary tumour was treated, with the median survival time after a metastasis diagnosis somewhere between five and 18 months.
So, it’s extremely important to identify which patients are part of the 50 per cent whose cancer will spread as soon as possible.
Unfortunately, testing for uveal melanoma metastasis has traditionally involved cutting a piece of tumour from the eye for biopsy. This is an invasive, risky, painful and often expensive procedure. There is a very real risk of vision loss resulting from an eye cancer biopsy.
Making matters worse, you only get one shot at an eye biopsy. If the material taken is not enough, or something goes wrong with the test, then you can’t cut the eye again.
As a result, screening levels and metastasis monitoring aren’t where we need them to be.
Blood test replaces biopsy
The situation improved in 2018, when scientists at Perth’s Edith Cowan University (ECU) developed a simple blood test that can achieve the same results as the biopsy – but without the need to cut your eye open.
The research team behind the test was able to identify specific genetic mutations in the 50 per cent of patients whose cancers metastasised, that weren’t present in patients with cancer that hadn’t spread.
This allows doctors to identify those most at-risk of having their eye cancer spread, and begin treatment earlier.
What are the genetic mutations responsible?
Dr Vivian Chua, ECU vice chancellor’s research fellow, says the prognosis for uveal melanoma patients whose cancer spreads is grim, mainly due to the lack of effective treatment options.
“The metastatic tumours respond poorly to many treatment options that had been shown to be effective in other cancer types including skin melanoma,” she says.
“Identifying the mechanisms that drive uveal melanoma metastasis will likely uncover strategies to prevent uveal melanoma spreading or the development of metastatic uveal melanoma, which is the cause of death of patients.”
Dr Chua’s research has identified that alterations to a gene known as BAP1 seem to be responsible for the cancer spread. BAP1 expresses a protein that is necessary to suppress the cancer spread, and the mutations detected impact its ability to do this.
BAP1 alterations have also been reported in other cancer types such as mesothelioma and cholangiocarcinoma.
Dr Chua compared two groups of human uveal melanoma cell cultures – one that contained normal levels of BAP1 and one that was deficient. She says the cells deficient in BAP1 grew slower and expressed less protein.
“We found that BAP1-deficient cells are slow-growing, and this was associated with the cells exhibiting low activity of the S6 protein. This is consistent with the known function of the S6 protein to regulate cancer cell growth,” she says.
“These characteristics were also associated with the BAP1-deficient cells surviving better under conditions deprived of amino acids.”
“Overall, we have uncovered a role of BAP1 deficiency in uveal melanoma,” said Dr Chua.
Dr Chua says she hopes her research will be able to contribute to the development of treatments to reverse BAP1 deficiency, and in turn, lower uveal melanoma.
Where you aware you could get a melanoma on your eye? Do you have any experience with eye cancer? Let us know in the comments section below.
Also read: If I’m diagnosed with one cancer, am I likely to get another?
