The retina, a thin layer of nerve tissue at the back of the eye, is critical for our ability to see. Unfortunately, it is also where retinoblastoma originates. Two doctors funded by TFRI have dedicated their careers to studying this childhood eye cancer, conducting groundbreaking research in the field.
Drs. Brenda Gallie and Helen Chan, both based at Toronto’s SickKids Hospital, have been investigating retinoblastoma for more than 40 years. The duo’s multi-centre research has helped bring Canada’s retinoblastoma mortality rate down to just one per cent.
Around 9,000 children are diagnosed each year worldwide, and 70 per cent do not survive. A lack of retinoblastoma awareness in developing countries, coupled with limited access to timely medical care, contributes to this staggering statistic – but TFRI funding has helped the team bring their best practice protocols to patients around the world.
“Terry Fox funding allowed us to take the molecular knowledge from the lab and apply it to patients worldwide,” says Dr. Gallie. “The genetic tests we developed in Canada with Terry Fox research funding have set the world standard.”
Retinoblastoma is caused by mutation in the RB1 gene, a tumour suppressor gene with the normal function to block many types of cancers. When both copies of the RB1 gene are damaged in a developing retina, retinoblastoma forms.
About half of all affected children are predisposed to get retinoblastoma because one RB1 is already damaged in all their normal cells - including the retina cells - resulting in multiple retinoblastoma tumors that usually affect both eyes (bilateral). Other children that carry two normal RB1 genes in their cells will develop only one tumor in the one eye with a damaged retina cell.
Genetic tests can accurately determine if each child has heritable or non-heritable retinoblastoma. Youth with a predisposition to retinoblastoma have heritable retinoblastoma, and their future children have a 50 per cent chance of receiving the damaged RB1 gene and also developing the disease, as well as a higher risk of being diagnosed with other types of cancers later in life.
Dr. Chan has made sure that childhood retinoblastoma survivors and their families are educated about these risks.
“I really value seeing the patients as they grow older, when they can discuss things with [me],” she says. “Remembering my patients as babies and seeing them grown up and eager to learn about the disease, I find that extremely gratifying [as a physician].”
Looking forward, the doctors say their ultimate goal is to take decades of TFRI-funded research and translate it into improved eyesight and treatment for future children diagnosed with the disease - both in Canada and around the world.
“What we’re aiming for with the next generation is to save both eyes…and also aim at as good vision as possible,” says Dr. Chan. “As we learn more and more, I am sure that we will be able to get less toxic and more effective treatments, and have better patient outcomes.”
Dr. Gallie agrees, noting she is very grateful for TFRI funding and donor dollars.
“On behalf of all the retinoblastoma families, patients and parents worldwide, I’d say thank you, thank you, thank you,” said Dr. Gallie. “We’re going to achieve, with Terry’s kick-start, optimal care for every child in the world with this rare disease.”
Project Title: The Terry Fox Program Project Grant: Oncogenes and tumor suppressor genes in mammalian development and progression of retinoblastoma
Investigators: Brenda Gallie, Helen Chan, Robert A. Phillips, Andy Becker, Jack Greenblatt, Jim Ingles
Project Title: The Terry Fox Research Institute Translational Cancer Research Project: Multicentre Phase II study for international intraocular retinoblastoma
Investigators: Helen Chan, Brenda Gallie, Elise Heon, Helen Dimaras, Tony Panzarella, The Hospital for Sick Children, OCI, and the University of Toronto