In a breakthrough, scientists have for the first time created cancer-killing cells which can be directly injected into patients.

Researchers in Japan have created cancer-specific killer T cells, the cells naturally occur in small numbers, but it is hoped injecting huge quantities back into a patient could turbo-charge the immune system, the `Daily Mail` reported.

Researchers at the RIKEN Research Centre for Allergy and Immunology revealed they have succeeded for the first time in creating cancer-specific, immune system cells called killer T lymphocytes, the `Daily Mail` reported.

To create these, the team first had to reprogramme T lymphocytes specialised in killing a certain type of cancer, into another type of cell called induced pluripotent stem cells (iPS cells).

These iPS cells then generated fully active, cancer-specific T lymphocytes. These lymphocytes regenerated from iPS cells could potentially serve as cancer therapy in the future, researchers believe.

Previous research has shown that killer T lymphocytes produced in the lab using conventional methods are inefficient in killing cancer cells mainly because they have a very short life-span, which limits their use as treatment for cancer.

To overcome the problems, Japanese researchers, led by Hiroshi Kawamoto reprogrammed mature human killer T lymphocytes into iPS cells and investigated how these cells differentiate.

The team induced killer T lymphocytes specific for a certain type of skin cancer to reprogramme into iPS cells by exposing the lymphocytes to the `Yamanaka factors` - a group of compounds that induce cells to revert to a non-specialised, stage.

The iPS cells obtained were then grown in the lab and induced to differentiate into killer T lymphocytes again. This new batch of T lymphocytes was shown to be specific for the same type of skin cancer as the original lymphocytes.

They maintained the genetic reorganisation, enabling them to express the cancer-specific receptor on their surface. The new T lymphocytes were also shown to be active and to produce an anti-tumour compound.

"We have succeeded in the expansion of antigen-specific T cells by making iPS cells and differentiating them back into functional T cells," Kawamoto said.
"The next step will be to test whether these T cells can selectively kill tumour cells but not other cells in the body. If they do, these cells might be directly injected into patients for therapy. This could be realised in the not-so-distant future," Kawamoto said.

The findings were published in the journal Cell Stem Cell.