Prostate cancer test hope

They have discovered a gene that triggers production of the AMACR protein in cancerous prostate cells.

The US team claim it is much more accurate than the prostate specific antigen (PSA) test currently used to detect prostate cancer.

Eventually, they say, a blood test for AMACR, eliminating the need for needle biopsies of the prostate, could be developed.

"It is most likely that many genes are involved in the development and progression of prostate cancer - each controlling a different step in the process "

Arul Chinnaiyan, University of Michigan

Prostate cancer is the most common male cancer affecting 21,000 in the UK each year and proving fatal for around 10,000.

The team from University of Michigan Medical School used advanced DNA microarray technology in their research.

The technique allows scientists to simultaneously screen large numbers of patient samples containing thousands of genes at once.

The AMACR protein is present in large amounts only in malignant cells and is easily visible when stained.

It is an enzyme involved in fat metabolism called a-methylacyl-CoA racemase, or AMACR.

It is the first time it has been linked with any type of cancer.

The researchers detected high levels of the AMACR protein in over 95% of more than 300 prostate tissue samples that contained localised cancer.

In benign prostate tissue, or tissue with non-malignant cell changes, there was either very little, or no AMACR protein.

The researchers tested tissues of 94 prostate needle biopsies, detecting the protein by staining. The tests were 97% sensitive.

AMACR is one of approximately 20 genes which are overexpressed consistently in prostate cancer.

The researchers found the AMACR protein was overexpressed in other cancers including bowel, ovarian, breast, bladder, lung, renal cell, lymphoma and melanoma - with the highest amounts present in bowel and prostate cancer.

'Cancer-specific'
Arul Chinnaiyan, associate professor of pathology at University of Michigan medical school, who worked on the research, said: "Previous prostate cancer studies focused on one gene at a time.

"With DNA microarray technology, we can look at thousands of genes in prostate cells simultaneously.

"This is important, because it is most likely that many genes are involved in the development and progression of prostate cancer - each controlling a different step in the process."

Mark Rubin, who also worked on the study, added: "The beauty of AMACR is that it is cancer-specific and concentrated only in malignant cells.