Stem cell shield 'could protect cancer patients'

By James Gallagher

Health and science reporter, BBC News

It may be possible to use "stem cell shielding" to protect the body from the damaging effects of chemotherapy, early results from a US trial suggest.

Chemotherapy drugs try to kill rapidly dividing cancer cells, but they can also affect other healthy tissues such as bone marrow.

A study, in Science Translational Medicine, used genetically modified stem cells to protect the bone marrow.

Cancer Research UK said it was a "completely new approach".

The body constantly churns out new blood cells in the hollow spaces inside bone. However, bone marrow is incredibly susceptible to chemotherapy.

The treatment results in fewer white blood cells being produced, which increases the risk of infection, and fewer red blood cells, which leads to shortness of breath and tiredness.

Researchers at the Fred Hutchinson Cancer Research Center, in Seattle, said these effects were "a major barrier" to using chemotherapy and often meant the treatment had to be stopped, delayed or reduced.

'Protective shields'

They have tried to protect the bone marrow in three patients with a type of brain cancer, glioblastoma.

One of the researchers, Dr Jennifer Adair, said: "This therapy is analogous to firing at both tumour cells and bone marrow cells, but giving the bone marrow cells protective shields while the tumour cells are unshielded."

Bone marrow was taken from the patients and stem cells, which produce blood, were isolated. A virus was then used to infect the cells with a gene which protected the cells against a chemotherapy drug. The cells were then put back into the patient.

The lead author of the report, Prof Hans-Peter Kiem, said: "We found that patients were able to tolerate the chemotherapy better, and without negative side effects, after transplantation of the gene-modified stem cells than patients in previous studies who received the same type of chemotherapy without a transplant of gene-modified stem cells."

The researchers said the three patients had all lived longer than the average survival time of 12 months for the cancer. They said one patient was still alive 34 months after treatment.

Cancer Research UK scientist Prof Susan Short said: "This is a very interesting study and a completely new approach to protecting normal cells during cancer treatment.

"It needs to be tested in more patients but it may mean that we can use temozolomide [a chemotherapy drug] for more brain tumour patients than we previously thought.

"This approach could also be a model for other situations where the bone marrow is affected by cancer treatment."

Memory loss and depression

Breast cancer rules rewritten in 'landmark' study

By James Gallagher

Health and science reporter, BBC News

What we currently call breast cancer should be thought of as 10 completely separate diseases, according to an international study which has been described as a "landmark".

The categories could improve treatment by tailoring drugs for a patient's exact type of breast cancer and help predict survival more accurately.

The study in Nature analysed breast cancers from 2,000 women.

It will take at least three years for the findings to be used in hospitals.

Cancer cartography

Researchers compared breast cancer to a map of the world. They said tests currently used in hospitals were quite broad, splitting breast cancer up into the equivalent of continents.

The latest findings give the breast cancer map far more detail, allowing you to find individual "countries".

"Breast cancer is not one disease, but 10 different diseases," said lead researcher Prof Carlos Caldas.

Analysis: What does this mean for patients?

The potential here is huge and it could have a transformative role in breast cancer care. However, we are a long way from using the new definitions in hospitals and the immediate impact on patients will be limited.

There are clear survival differences among the 10 categories. Clusters two and five seem to have a 15-year survival of around 40%. Clusters three and four have around 75% survival over the same period. This could help better inform patients.

In terms of treatments, there is bad news. There is a targeted therapy for just one of the 10 breast cancers groups. That is Herceptin, which is already used in a targeted group of patients. Other groups will still have "standard" therapies such as chemotherapy or radiotherapy.

The hope is that by identifying the 10 breast cancers it will be possible for researchers to design drugs for each one, but that is still a work in progress.

He added: "Our results will pave the way for doctors in the future to diagnose the type of breast cancer a woman has, the types of drugs that will work and those that won't, in a much more precise way than is currently possible."

At the moment, breast cancers are classified by what they look like under the microscope and tests for "markers" on the tumours.

Those with "oestrogen receptors" should respond to hormone therapies such as tamoxifen; those with a "Her2 receptor" can be treated with Herceptin.

The vast majority of breast cancers, more than 70%, should respond to hormone therapies. However, their reaction to treatment varies wildly. Prof Caldas said: "Some do well, some do horribly. Clearly we need better classification."

Unprecedented scale

His team looked at frozen breast cancer samples from 2,000 women at hospitals in the UK and Canada.

They looked in huge detail at the genetics of the tumour cells - which genes had been mutated, which genes were working in overdrive, which were being shut down. Read more…

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