Cancer Research UK : Stem cells in cancer research

Stem cells in cancer research

We often hear about stem cells in the media, from their potential to treat human disease to the ethical issues surrounding the production and use of embryonic stem cells. But what part do stem cells play in cancer research?

What are stem cells?

Embryonic stem cells
Adult stem cells

Why do scientists study stem cells?
How could stem cell research help to beat cancer?
Stem cell research funded by Cancer Research UK
Examples of Cancer Research UK-funded stem cell research

What are stem cells?

A stem cell is a kind of 'starter cell' that has the potential to develop into many different cell types in the body. When a stem cell multiplies, the resulting cells either remain as stem cells or, under the right conditions, can become a type of cell with a more specialised function, such as a muscle cell, red blood cell or brain cell.

Stem cells occur naturally in the body in various places and stages during our lifetime. They can broadly be divided into two categories: embryonic stem cells and adult stem cells.

Embryonic stem cells

Embryonic stem cells are found in early stage embryos that are a few days old. These remarkable cells give rise to all the different tissues and organs of the body. The generation and use of human embryonic stem cells is controversial and tightly regulated. In the UK, the Human Fertilisation and Embryology Authority (HFEA) governs the use of human embryos and stem cells for research.

Many researchers working in this field use either mouse embryos as a source of stem cells, or work on existing human embryonic stem cell lines that were generated in the past. Some scientists are also exploring the potential of stem cells taken from the blood in the umbilical cord.

Adult stem cells

Adults also have some stem cells, but these have a more limited repertoire, with each type of stem cell only able to develop into a specific subset of cells. For example, adult stem cells in the bone marrow, known as haematopoietic stem cells, can usually only give rise to different types of blood cell – though some scientists have recently found ways to convert them into kidney or liver cells as well.

Because adult stem cells can be produced without the need to use embryos, their use in research has fewer ethical complications. But because they can only develop into a limited number of cell types, some researchers argue that this makes them less useful.

Dr Lilian Clark, Cancer Research UK's executive director of science, said: "Although most cancer scientists' stem cell research currently involves adult stem cells, future patients with serious illnesses including cancer could benefit from research involving embryonic stem cells.

"We therefore believe that the necessary research should be permitted within a well-regulated environment."

Why do scientists study stem cells?

There are a number of reasons why stem cells have the potential to be very useful in scientific and medical research. Firstly, because stem cells can effectively grow forever, they can be grown in the lab without the need to constantly go back and isolate fresh new stem cells. This enables scientists to have a constant supply of cells for their experiments.

Also, as stem cells can grow into other cell types, scientists can potentially treat them in a certain way to turn them into the types of cells that they want to use. Cells generated in this way have several potential medical applications, as well as use in research. For example, in the future scientists may be able to use stem cells to generate more brain cells for people with conditions such as Parkinson’s disease.

One day it may even be possible to grow new organs in the laboratory for people who require transplants. If scientists were able to use the patient's own stem cells to make the new organ, they would potentially overcome some of the problems of transplant rejection.

And it is also possible that researchers will one day be able to overcome the effects of faulty genes in cancer and other diseases by encouraging stem cells with a correct version of the gene to develop into the type of cell to be replaced.

How could stem cell research help to beat cancer?

As well as the examples above, stem cells have considerable potential for cancer research and for improving the treatment of the disease. Cancer cells share many characteristics with stem cells – including, and perhaps most importantly, the fact that they are 'immortal'. So understanding more about stem cells can help us to learn more about cancer.

Scientists also now believe that stem cells may play a direct role in the development of cancer, as some tumours are thought to develop when normal stem cells become faulty. This has led to the idea of 'cancer stem cells', which have now been identified in a range of cancer types, including bowel, breast and prostate cancer.

Researchers think that some cancers may be made up of a population of cancer stem cells, as well as 'bulk' tumour cells. It is possible that many cancer treatments only kill the bulk cells, and fail to tackle the cancer stem cells. This could explain why some cancers can start growing again after treatment.

The challenge for scientists is to understand where cancer stem cells come from, and to devise ways to target them with effective treatments. To do this, they need to study the molecular makeup and behaviour of stem cells in great detail.

Stem cell research funded by Cancer Research UK

Cancer Research UK does not fund any research that uses human embryos or foetal tissue. However, we are funding a small number of research projects that are using human embryonic stem cell lines grown in the lab. These cell lines were originally produced from human embryos by other scientists.

A few researchers funded by the charity are studying embryonic stem cells made from mouse embryos. Others are investigating the role of adult stem cells in cancer.

Here are some examples of Cancer Research UK-funded stem cell research.