Key genetic clue in fighting prostate cancer

US researchers have made a discovery that might help doctors distinguish between benign and more aggressive forms of prostate cancer. The team reports that a difference in the genetic make-up of prostate tumours could indicate which are likely to metastasize and spread through the body, and which will be slow-growing and non-fatal.

Professor Lloyd Trotman and his colleagues at Cold Spring Harbour Laboratory in New York used a mouse study to identify a novel tumour-suppressing gene, 'PHLPP1' (pronounced FLIP or FILIP), that acts alongside a known prostate tumour-suppressor, PTEN.

When prostate cancer patients have mutated forms of PTEN, their tumours will grow out of control.

Another gene known to be involved in the progress of prostate cancer is p53; when it is mutated, prostate cancer becomes metastatic, and it is this knowledge that 'led us to ask whether there are specific rules for prostate cancers to become lethal', said Professor Trotman.

Approximately 250,000 men in the UK live with prostate cancer, but only a small percentage of these cases will become metastatic and — therefore - are likely to be lethal, reports the Independent newspaper. A test enabling doctors to tell which prostate cancer patients' tumours are likely to metastasize could prompt earlier and more appropriate treatment, saving lives.

'The ideal scenario is to be able to detect what we are looking for by taking blood samples, although that may prove to be too late. It might be better to pick up metastatic tumours by taking small biopsies from the prostate gland', Professor Trotman said.

Professor Trotman and his colleagues, whose results are published in the journal Cancer Cell, used over 200 prostate cancer samples gathered at the Memorial Sloan-Kettering Cancer Center in New York to investigate the relationship between PTEN and PHLPP1 in human tissue, and found that both genes were very frequently mutated or deleted in metastatic tumour tissue.

The results could be used to influence which drugs are used in which prostate cancer patients and when, according to a press release from Cold Spring Harbour Laboratory. Researchers have shown that drugs that inhibit mTORC1 proteins, which regulate cell proliferation and motility, could hinder PHLPP's cancer-progressing action.

'Our study argues for checking a patient's PHLPP status before giving him these drugs', said Professor Trotman. 'We need to start assessing treatment options based on whether or not the patient's molecular backup route is still intact'.