Tumour-killing virus could stop a childhood eye cancer and save vision

https://www.newscientist.com/article/2191617-tumour-killing-virus-could-stop-a-childhood-eye-cancer-and-save-vision/

Cecilia Hipolito Lucas, who suffers retinoblastoma plays in a shelter for chronically ill children in Mexico City, Mexico

Retinoblastoma is a rare eye cancer usually diagnosed before the age of 3

Chico Sanchez / Alamy Stock Photo

A cancer-killing virus may be able to remove tumours associated with retinoblastoma, a rare eye cancer usually diagnosed in children before the age of 3. The hope is that this approach will prevent the need for eye removal surgery to stop the cancer from spreading to the brain.

Currently, chemotherapy is the first line of attack, but this fails in around 30 per cent of cases because the tumour becomes resistant to the drugs, leaving surgery as the only remaining option. Children who have the type of retinoblastoma based on an inherited genetic mutation, which leads to tumours in both eyes, are often left blind after both eyes are surgically removed.

Cells with the genetic mutation that leads to retinoblastoma have a specific marker, so Angel Carcaboso at the Sant Joan de Déu Research Institute in Barcelona and his team engineered a virus to only replicate in the presence of that marker. That allows the virus to only affect the cancerous cells, and leave the surrounding tissue intact.

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In animals, the team showed that the virus stayed in the eye into which it was injected and that the side effects of the virus were mild and reversible. They also confirmed the virus’s tumour-killing capabilities in human cells in the lab.

The team then tested the treatment in two children who were both 2 years old and were candidates for eye removal surgery. Though they saw promising effects, including small tumours diminishing or disappearing, both children ultimately had to undergo eye removal surgery.

Carcaboso says they will need to finish the clinical trial, which includes 13 patients, to see if a higher dose of the virus is more effective.

Journal reference: Science Translational Medicine, DOI: 10.1126/scitranslmed.aat9321

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