Retinoblastoma – advancing understanding of causes, progression and malignancy
Prof. Shin-ichi Ohnuma & Mandeep Sagoo | GR000113
We are delighted to be supporting the research of Professors Shin-ichi Ohnuma and Mandeep Sagoo, who are studying retinoblastoma (RB) – the commonest eye cancer in children. They are looking at how genetic changes can influence disease prognosis or response to treatments. This work could ultimately help with the development of more targeted therapies and better treatment for this type of cancer.
What is retinoblastoma?
Retinoblastoma is a rare type of eye cancer that can affect young children, usually under the age of 5. It is a cancer of the retina, the light-sensitive lining at the back of the eye. It can affect 1 or both eyes. One of the signs of retinoblastoma is an unusual white reflection in the pupil of the eye.
In 40% of cases, RB is caused by a faulty gene (rb1), which often affects both eyes (bilateral). It may be inherited by the parent, or a change to the gene may occur at an early stage of the child’s development in the womb. It is unclear what causes RB in children without the faulty rb1 gene.
Professors Ohnuma and Sagoo aim to identify other gene mutations that cause the condition and what influences the aggressiveness of the progression and malignancy of RB.
We do know that, in some cases, this cancer is due to a mutation of the rb1 gene, which is responsible for making a protein in our bodies called pRB. This protein regulates cell growth and keeps them from dividing too fast, effectively acting as a tumour suppressant.
However, mutation of the rb1 gene alone is not sufficient to result in the progression to cancer, nor has it been linked to all forms of RB. Furthermore, some RBs are very aggressive, whilst others are not; some patients develop RB in both eyes, while it develops for some in only one eye; and treatments are very effective for some people, but others are resistant. The reason for these differences is unclear.
Finding a solution
This research will use cutting-edge gene sequencing technology to try and better understand retinoblastoma. It will analyse genetic and clinical data to determine if there are any correlations that exist between genetic mutations and clinical presentations.
Using samples from patients, they will also look at when RB growth moves from benign to cancerous form. Using further genetic and cellular techniques, the research team will aim to delve into where the cancer cells originate and further investigate other possible genes involved in RB, such as the tumour suppressor gene PRELP.
The long-term aim of this investigation is to help drive the development of targeted treatments to better cure retinoblastoma and avoid the loss of one or both eyes – and in rare circumstances, prevent death.
Achievement of these aims could possibly allow for the implementation of new diagnostic methods to predict the relative malignancy of RB tumours, allowing molecularly targeted treatments for the first time.
Additionally, the identification of new cancer modifying genes will provide material to further study new cancer treatments in the fight against childhood eye cancer.
With this research well underway, the team have published findings from some of their work in Cancers, an open access journal of oncology:
This paper reports on the power of gene sequencing technology. They describe how standard clinical screening techniques can identify the majority of rb1 mutations. However, in those cases where rb1 mutations remain undetected, an extensive search using whole genome sequencing may help provide vital answers for the patient.
Photo courtesy of Childhood Eye Cancer Trust
Research Project Grant
Shin-ichi Ohnuma & Mandeep Sagoo