The prostate specific antigen test for monitoring prostate cancer and its progression has some limitations. Now scientists have discovered a new biomarker that is based upon the genetic material of a tumor and, moreover, it is excreted in the urine in tiny fat particles. This research might lead to an easier and more reliable biomarker test to show which prostate cancers need more aggressive treatment. There are many options in the treatment of prostate cancer. Radical surgery, chemotherapy and radiotherapy, or just ‘watchful waiting’ are all approaches which may be needed. But doctors do not want to over-treat, because invasive treatments can have long-term side effects like impotence and incontinence. But nor should aggressive tumors be under-treated. That is why, in prostate - and other - cancers, the search is on to distinguish which tumors are growing fast and which are more dormant. Tumor cells have distinct genetic signatures which are beginning to be accessible to research through new technologies that can readily analyze the activity of many genes at once.

A new biomarker for prostate cancer?

The prostate specific antigen (PSA) test has long been used to detect and monitor prostate cancer. PSA is a protein secreted by the prostate gland and levels can be elevated if cancer is present and measurements can be used to grade the cancer according to its aggressiveness and monitor response to treatment. But many clinicians point to the limitations of the PSA test - low levels may still conceal a cancer, while high levels can lead to false alarms. That is why the search is on for better biomarkers for prostate cancer. Jonas Nilsson and his team at the VU University Medical Center in Amsterdam have been studying genetic material, known as RNA, within tiny bubbles of fat called exosomes. These are found in the urine of people with and without cancer, and are excreted in large quantities by some cancer cells - potentially providing material to study the genetic signature of a cancer through analyzing the RNA within an exosome. Well, this study means that Nilsson’s work is at an early stage. But finding a potential biomarker in urine opens up the possibility of developing a rapid and accurate biomarker-based test to determine how aggressive a prostate cancer is likely to be. Treatment can then be matched to the type of tumor at an early stage - sparing unnecessary treatment to those with less aggressive tumors, but hitting tumors hard if this is appropriate.