LONDON: Scientists have discovered how a genetic switch that allows cancerous cells to divide and spread works, in a finding that could open up a new avenue to treat many of the most common cancers.

The switch controls an enzyme called telomerase.

In normal cells, the gene that regulates it is tightly packaged and coiled and the switch is off, so the enzyme is not produced and the cells can only divide a finite number of times.

But British and Swiss researchers found that cancer cells manage to unravel the gene and flip the telomerase switch back on, and that blocking the process cuts off the enzyme and cancerous cells stop multiplying.

“The discovery of how the switch works is what we have done and of course that has implications for therapies because there is a great interest in new drugs that will modify the way genes express (or work),” Professor Robert Newbold, of Brunel University north of London, told Reuters.

Cancer develops when the control signals in a cell go wrong and it mutates. Instead of destroying itself, the cell multiplies uncontrollably and forms a tumour. Although there are more than 200 types of cancer, they all start in the same way.

Newbold and scientists from the Swiss Cancer Research Institute in Lausanne flipped off the telomerase switch in cancerous cells in the laboratory by adding genes from normal cells that made the telomerase gene recoil into its compact form.

“We know that if we stop telomerase working in cancer cells they stop dividing. The question is how we go about stopping it,” added Newbold, whose research is reported in the journal Cancer Research.

NEW DRUGS: The scientists believe that a drug that targets the gene and the way it is packaged could switch off telomerase in cancerous cells.