By identifying this group of very aggressive tumours, we've given ourselves the opportunity to hopefully give more of our young patients the chance of life

Dr Carmel McConville

The discovery paves the way for doctors to test for the genetic fault that causes these aggressive cancers.

This could enable them to treat affected children as effectively as possible, while sparing those with milder forms of the disease from the harshest therapies.

Scientists also hope that the discovery of a new form of the disease will lead to brand new treatments targeted against its genetic causes.

Nervous tissue

Neuroblastoma, which accounts for 13% of children's cancer deaths, is a cancer of immature nervous tissue that most commonly develops in the adrenal gland, next to the kidneys.

The researchers believe that over a third of these cancers may belong to the newly identified, aggressive group.

Lead researcher Dr Carmel McConville, of Birmingham University, said: "The key to treating neuroblastomas successfully is to work out how they are likely to respond to treatment, and to adjust drug and radiotherapy regimes accordingly.

"By identifying this group of very aggressive tumours, we've given ourselves the opportunity to direct treatments towards it, hopefully giving more of our young patients the chance of life."

Scientists have known for some time about one aggressive type of the disease - called MYCN amplified neuroblastoma - which accounts for about a quarter of all cases.

Genetic changes

But when the Birmingham researchers looked at the remaining three quarters, they found a huge variation in the rate of survival.

They suspected that some of these children had an aggressive type of neuroblastoma and others a less aggressive form.

The scientists analysed chromosomes in the cells of 28 children's nervous tissue cancers, to see whether any genetic changes were particularly common.

They then checked whether these changes were associated with the aggressiveness of tumours and their responses to treatment.

They discovered that in 36% of tumours, a piece of one of the chromosomes (chromosome no. 11) was missing, while many of these also had a number of other genetic changes.

This group of tumours was distinctly different from the MYCN amplified cancers and was even more aggressive.

Three different types

The scientists concluded that there were three different types of neuroblastoma:

• MYCN amplified cancers
• the newly discovered type with a missing piece of chromosome 11
• a much less deadly form