Lymphoma – a cancer of the blood – is one of the most common types of cancer in Singapore, with two or three new cases diagnosed every day.
For some types of the disease, the best way to fight it is immunotherapy, an increasingly popular treatment which involves using drugs to boost the immune system to combat cancer cells.
But this can be expensive here – around $10,000 a month – and is not suitable for all types of cancer, meaning some patients waste large sums on treatment that does not work, as well as precious time.
However, a local group of experts believe that by the end of this year, a test costing less than $1,000 will be able to determine whether a patient suffering from a particular subtype of lymphoma will respond to the treatment.
In 2016, clinical scientists from the Singapore Lymphoma Translational Study Group (Symphony) discovered that a genetic mutation present in patients suffering from the NK/T-cell lymphoma is the reason immunotherapy works well for them.
To date, the researchers have performed whole genome sequencing on 60 patients with NK/T-cell lymphoma and discovered that up to a quarter of tumours carry this genetic alteration.
“The genetic variation, known as PD-L1 3’UTR SR, increases the growth of a type of protein called PD-L1 on individual cancer cells and shields them from attacks by the body’s immune cells,” said Dr Ong Choon Kiat, a scientist from the National Cancer Centre Singapore involved in the research.
This allows the cancer cells to escape under the radar of the body’s immune system and multiply.
Blocking these proteins with monoclonal antibodies allows the cancer cells to be rediscovered and destroyed by the immunity cells.
So far, immunotherapy has worked for seven out of 13 research patients who were unresponsive to conventional treatments such as chemotherapy and radiotherapy.
The team also identified genetic alterations activating the JAK/ STAT pathway – an important cellular signalling process that promotes the growth of cancer cells.
Patients with these gene alterations were also found to respond better to immunotherapy than patients without.
The team, which received a $10 million grant from the Ministry of Health’s National Medical Research Council last month, is working with local biotech company Lucence to develop a test for the genetic variation and identify suitable patients for the treatment.
The platform uses a combination of DNA amplification and next-generation sequencing technologies to test genetic variations in patients.
Professor Lim Soon Thye, Symphony’s corresponding principal investigator, said: “It is important to understand that not all patients will respond to immunotherapy, and the population of patients who respond to this treatment will depend very much on the type of cancer.
“By identifying patients who would respond to immunotherapy, we can avoid unnecessary cost and loss of precious time for them.”
Symphony comprises clinicians and researchers from Singapore, China, Taiwan and South Korea. They conduct research on peripheral T-cell and NK/T-cell lymphomas – subtypes of the disease that are more common in Asia compared to the West.
Lymphoma is the fifth most common cancer in the male population here and the sixth most common cancer in the female population, according to the Singapore Cancer Registry between 2011 and 2015.
Studies have shown that the incidence rate is increasing at 3 to 4 per cent annually in Singapore.
There are currently about 900 new cases every year.