Cancer treatment breakthrough

Test analyses the patient's genetic structure

Scientists have developed a test that can tell if cancer patients are likely to respond to the most common drug treatment.

A version of the test, developed by UK firm Virco, could soon be routinely used by doctors.

The test detects whether a particular gene, the MGMT gene, has a molecule called methyl attached to it.

This has the potential to be turned into a diagnostic tool that could help improve cancer therapy significantly

Professor Steven Baylin, Johns Hopkins University, Baltimore

Research carried out by Virco showed that brain tumour patients who tested positive for the methyl molecule were 16 times more likely to respond to treatment with the most common form of chemotherapy.

They were also ten times less likely to die during the three years of follow-up than were those who tested negative.

The chemotherapy drugs in question are called alkylating agents.

They work by attaching to the genes in cancer cells, causing various changes that lead to the death of the cancer cell.

If the MGMT gene has no methyl attached it can switch on a repair process which counteracts the effect of the alkylating drug.

Diagnostic tool

The research was conducted at the Comprehensive Cancer Research Center at Johns Hopkins University in Baltimore, Maryland.

Professor Steven Baylin, one of the lead researchers, said: "This has the potential to be turned into a diagnostic tool that could help improve cancer therapy significantly.'

Virco is now developing a routine version of the test to help doctors target alkylating drugs for those patients who test positive for methylated MGMT genes.

In addition a drug to inhibit the MGMT gene and re-sensitise the patient to treatment with alkylating agents is under development.

The study researchers chose to examine brain tumour (glioma) patients because methylation of the MGMT gene is common in this type of cancer.

The findings could potentially help to tailor the treatment of a number of other common cancers, including lymphomas, lung, head and neck, and colorectal cancers.

Positive reaction

Dr Victoria Wilson, of the Cancer Research Campaign, told BBC News Online: "The ability of our cells to repair DNA damage is one of the major reasons for the failure of treatment with some of our most commonly used anti-cancer drugs, and temporarily switching off repair is one approach that is being actively investigated.

If this diagnostic test can really deliver what it promises it would be a valuable addition to the techniques available to doctors

Dr Victoria Wilson, Cancer Research Campaign

"What's interesting about this approach is that it will allow doctors to distinguish two sub-groups of patients with different abilities to repair damage caused by chemotherapy and to select the best treatment for each group.

"Any new marker that enables doctors to predict who will respond to a particular drug and help target the most appropriate treatment to each patient is certainly welcome.

"If this diagnostic test can really deliver what it promises it would be a valuable addition to the techniques available to doctors."

The research is published in the New England Journal of Medicine.