Doctors in Britain have come up with a "magic bullet" treatment that can target forms of leukaemia.
They are now confident a similar approach might work against lung and breast cancer.
The research was carried out by teams from London's Hammersmith Hospital and Imperial College School of Medicine and was funded by the UK's Leukaemia Research Fund.
The key finding is the discovery of a single gene called WT-1 which becomes overactive in the cells that cause leukaemia. This enables the researchers to easily identify and then target the cells for destruction.
In a proposed two-part treatment, the doctors first take killer T-cells, a form of white blood cell, from a healthy volunteer and engineer them so they recognise and attack only those cells which over-express the WT-1 gene. When these white cells are injected into a patient, they kill off the leukaemia cells and leave normal tissues untouched.
The patient's own killer Tcells don't respond to the leukaemia but the introduced cells mount a vigorous attack. The donated cells aren't destroyed because the patient is given immune suppression treatments which keep the donor cells healthy long enough to do their work.
Tests so far have been in the laboratory but the first trials on humans are planned to begin within two years. "The principle we have developed can be applied to almost all forms of leukaemia and could signal a huge step forward in how we treat the disease," said Dr Hans Strauss of Imperial College.
"What makes this work even more exciting is that our findings can be applied to solid cancers where there is similar overexpression of WT-1. The possibilities for new treatments are enormous," he said.
There were opportunities for treatments against persistent and difficult-to- treat cancers including those in the lung, Dr Strauss said.
"This is the chink in the armour cancer doctors have been looking for," said Dr David Grant, scientific director of the Leukaemia Research Fund.
The so-called magic bullet against cancer has long been sought by researchers but has proved difficult to achieve. The idea is to have a targeted treatment that would kill only cancer cells.
It is based on using the complex biochemistry inside cells, but targeting has been confounded by similarities between healthy tissue and diseased tissue. The cells were too similar for earlier treatments to differentiate between the two.
The new approach based on the WT-1 gene gets around this. While the gene exists in healthy tissues it is greatly over-expressed in cancer cells, thus putting up a flag that can be identified by the killer T-cells.
