Protein key to cancer growth say scientists

The enzyme, known as PI-3 kinase gamma, is believed to play a key role in the process by which inflammation fuels tumours.

Blocking the protein in animal studies led to dramatic reductions in tumour growth, progression and spread.

Scientists believe the molecule could provide a new therapeutic target for most, if not all, solid tumour cancers.

The discovery builds on increasing evidence that inflammatory action by the immune system can make cancers more aggressive.

American and Italian researchers identified a mechanism whereby myeloid-immune cells enter tumours and accelerate their growth and ability to spread around the body.

The spread, or metastasis, of tumours to vital organs is the most common cause of death from cancer.

PI-3 kinase gamma operates like a “switch” that allows myeloid cells to invade tumours.

When its action was blocked, either genetically or through the use of a drug, cancer growth was held back. Scientists also saw a dramatic decrease in metastasis.

The research was published yesterday in the journal Cancer Cell.

Study leader Professor Judith Varner, from the University of California at San Diego, said: “It could be a very important therapeutic target for future cancer treatments and could impact most, if not all, types of solid cancer.”

A number of biotechnology companies are already developing drugs that inhibit PI-3 kinase proteins to treat cancer, heart disease and arthritis.

The PI-3 kinase gamma enzyme may be a particularly promising target because blocking it is not likely to produce many side-effects, said the scientists.