NEW drugs being developed to treat prostate cancer may not be targeting the main cause of the disease, according to research by scientists in York.

Studies at the University of York have suggested a process called “methylation”, which was previously believed to drive the development of cancer, occurs in cells which already cancerous.

The team which researched the issue said their findings mean therapies designed to reverse this process might not be effective against cancer stem cells and the condition could return.

The work was carried out by Dr Davide Pellacani and was published this afternoon, funded by Yorkshire Cancer Research and the Grand Masonic Charity.

It said a major difference between cells normally treated in cancer and underlying stem cells had been revealed. Dr Pellacani, a member of Professor Norman Maitland’s team at the Yorkshire Cancer Research Unit at the university’s department of biology, said it could have implications for the effectiveness of new drugs which are intended to change the methylation pattern in cancers.

Methylation is a process where DNA is changed to block instructions for making a specific protein. Dr Pellacani said: “To develop cancer, certain proteins found in healthy cells need to be switched off, and sometimes this is caused by methylation.

“There are obvious differences in the methylation of genes in prostate cancer cells and non-cancer cells. This suggested the process could be driving the progression of cancer and that this could be reversed by using specific drugs, but our research has suggested this may not be the case.”

He said there were “clear implications” for new drugs currently being developed, and the only way of moving towards long-term treatment or even a cure for cancer was to treat all cancerous cells.

Professor Maitland’s team were internationally recognised in 2005 when they were the first to identify prostate cancer stem cells, believed to be the root cause of the disease. Yorkshire Cancer Research provided the unit with a £2.15 million grant to carry out further work.

The National Institute of Clinical Excellence and the Medicines and Healthcare Products Regulatory Agency said the development of new drugs was not an area they were involved in, with the Department of Health also not commenting.