Dr Marissa Teo trains cells to detect and destroy cancer cells

SHE runs an army of cells, trained to detect cancer cells and then attack and kill them.

Dr Marissa Teo, a post-doctoral researcher, tends to colonies of white blood cells, taken from those suffering from nasopharyngeal cancer (NPC), a type of nose cancer.

What she does in the lab is important as it enables doctors here to offer NPC patients a new type of therapy.

Dr Teo trains and grows these patients’ white blood cells in the clean laboratory at the National Cancer Centre Singapore (NCCS) to attack only NPC cells.

For her work, Dr Teo 33, became the first Singaporean to be awarded the Unesco-L’Oreal For Women in Science International Fellowship, first given out 12 years ago.

Unesco, founded in 1945, is the United Nations Educational, Scientific and Cultural Organisation.

Accepted award
She travelled to Paris to accept the award at the Unesco headquarters in early March.

Now back in Singapore, she is excited about her demanding work.

Said Dr Teo: “Cancer is on the rise in the region and and there is an ever increasing need for research into cancers that are more common here than in the West.”

Cancer is the leading cause of death in Singapore. About 9,000 people here are told each year that they have the disease.

Dr Toh Han Chong, her boss at the department of medical oncology at NCCS, had nominated Dr Teo for the award.

Said Dr Toh, the head and senior consultant at NCSS: “What we’re doing is extracting T-cells (white blood cells) from the patient’s own blood, then ‘educating’ these cells recognise certain viral proteins.

“These T-cells will be expanded into large numbers in the lab and infused back into the patients to fight the cancer.” (See graphics).

Likening the entire operation to growing an army, Dr Toh said: “If we see the T-cells as fresh recruits, what we’re trying to do is train
themto recognise a specific enemy.”

Once this is done, Dr Teo and her team will build up the fighting force from platoon to battalion to division strength.

“For each patient, we will grow their educated  T-cells into the billions. When they reach the battlefield, they will know how to ‘seek and destroy’ the enemy while sparing the innocent cells in their midst,” said Dr Toh.

The T-cell therapy process is simple for the patient.

All that is needed from the patient is blood, about the volume of a soft drink can, about 330ml.

The difficult part – the culturing and growing of the T-cells – will take four months. After which, the T-cells are infused back into the
patient.

It is hoped that this process, coupled with a course of chemotherapy, will significantly extend survival rates for those with stage four
NPC who have not had any other treatment, said Dr Toh.

The treatment can be used only on stage four cancer patients. For the moment, it is also used only on NPC.

The T-cell therapy is now being tested in a phase II clinical trial for which Dr Toh hopes to get 38 advanced NPCpatients.

According to Dr Toh and Dr Teo, NPC was chosen for two reasons.

It is the sixth most common cancer in Singapore, and is endemic in southern China and South-east Asia. It is a cancer that is largely ignored in the west because of low numbers.

NPC also has a detectable weakness. On the surface of NPC cells sit Epstein-Barr related viral proteins (EBV).

The EBV can be used to train the T-cells to recognise NPC cells as targets.

Said Dr Toh: “Most people become infected with EBV at some point in their lives. Of those affected, the majority suffer nothing more than mild afflictions, such as fever, sore throat or swollen lymph glands. However,
some carriers of the virus eventually develop NPC.”

T-cell therapy could spare patients from complications resulting from radiotherapy and chemotherapy treatments such as hearing loss, jaw-muscle deadlock and tooth decay.

Reduce relapse
It could also reduce the incidence of a relapse.

“We are the only centre in Asia that is growing T-cells to treat NPC,” said Dr Toh.

NPC affects 300 people a year here and recurs in about 70 per cent of patients, as some cancerous cells still survive.

Dr Toh and his team are also studying why some patients respond to the therapy and some don’t.

“We are investigating a tracking system to detect whether the T-cells actually get to the cancer it’s supposed to get to,” he said.

Dr Teo’s award comes with a US$20,000 ($27,900) research grant with the Baylor College of Medicine in the United States.

She will go there in May to further her research in this area of T-cell therapy.

Dr Teo is among this year’s 15 winners of the Unesco-L’Oreal award. They were picked from 150 nominees.