Aggressive prostate cancer gene identified

Finnish researchers have identified two possible mutations in one gene that are both correlated with prostate cancer.

Prostate cancer is the sixth most common cause of male cancer-related death worldwide. Heritability is estimated to make up 57 percent of the risk but few biomarkers are available to diagnose aggressive disease. Identifying relevant mutations could improve diagnostic tests.

'Those with the more aggressive forms of prostate cancer have the bleakest outcome but if we can devise tests to diagnose them early on, we can do more to ensure they receive the best possible treatment,' Helen Rippon, chief executive of the Worldwide Cancer Research charity, which helped fund the study, told the Times.

Over 100 susceptibility mutations had already been identified in the human genome, but only a few have been shown to affect disease severity and outcome. 

In recent research, published in the International Journal of Cancer, a Finnish research team sequenced a gene called ANO7 that they suspected was involved in prostate cancer. The researchers used DNA samples from over 1700 Finnish prostate cancer patients alongside samples from a similar number of unaffected men. The results were validated against a larger sample group of over 5000 Swedish and Norwegian patients and 1400 further controls.

Within ANO7, the scientists found one mutation that correlated with an increased risk of developing prostate cancer, as well as disease severity. A second mutation correlated with shorter survival time. 

Additionally, 22 prostate tumour samples were analysed for ANO7 gene expression. Gene expression was found to be highly raised in prostate cancer tumours compared with normal prostate tissue, and higher expression correlated with patient mortality rate. 

'Genetic testing for ANO7 could help identify these patients sooner and may bring new opportunities for precision oncology in prostate cancer,' said lead author Professor Johanna Schleutker of the Institute of Biomedicine of the University of Turku. 

One limitation of the study is that the subjects were all Northern European Caucasian patients. The researchers suggested that people of other ethnic backgrounds should also be studied before screening for ANO7 can be recommended.