For men, prostate cancer accounts for 25% of all cancer cases. But diagnosing the cancer is not without controversy.

The usual method of detecting the cancer is by screening for Prostate-Specific Antigen (PSA), which can lead to early detection and treatment of the disease. Some studies have shown that the PCA test results in high amounts of overdiagnosis (see this article at NPRs All Things Considered) , making it extremely inefficient, although the prostate cancer mortality rate has decreased. So it’s not the perfect technique, but it stands as a standard.

The other point to consider is that there is an aggressive form of prostate cancer and an indolent form, which remains in the prostate. Although the majority of cases are indolent prostate cancer, the aggressive form is the second leading cause of cancer deaths in the US. Being able to clearly distinguish risk factors for aggressive versus indolent forms of the cancer is clearly beneficial.

Similar to other association studies, geneticists have tried to find specific genetic variants (markers) that are present in patients with prostate cancer but not in unaffected individuals. This is interesting but of limited use because markers that distinguish the aggressive and indolent form were not assessed.

In the most recent study published in the Proceedings of the National Academy of Sciences, Jianfeng Xu and coleagues address this problem by specifically comparing aggressive and non-aggressive patients. This uncovered a single nucleotide difference that clearly distinguished the patients with the two forms of prostate cancer.

This has finding has two clear implications. That there are genetic determinants that distinguish indolent and aggressive forms of prostate cancer, and that they can potentially be used as markers for each type. However, because the separation is not 100% (i.e. the marker is not only found in aggressive forms, but sometimes in patients with the indolent form) further studies will need to refine the use of this marker as a diagnostic tool.

Image: The Prostate Cancer Awareness Ribbon (via Injuryboard.com)

See also: Gene may pinpoint most aggressive prostate cancer on Reuters

See also: All about prostate cancer at The American Cancer Society

Citation:

Xu, J., Zheng, S., Isaacs, S., et al. (2010). Inherited genetic variant predisposes to aggressive but not indolent prostate cancer Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0914061107