Researchers have discovered a gene that appears to be associated with prostate cancer and how fast it grows. Overactivity of this gene appears to cause cells to divide uncontrollably – resulting in cancer. It is hoped that a test for this gene’s activity could be developed that could be used to identify prostate cancer and distinguish between slow-growing and fast-growing tumours.
The work was conducted by researchers at the Institute of Cancer Research Everyman centre and have been published in the journal Oncogene (Foster CS, Falconer A, Dodson AR. Transcription factor E2F3 overexpressed in prostate cancer independently predicts clinical outcome. Oncogene advance online publication, 7 June 2004).
What is prostate cancer?
The prostate is the gland that produces the liquid component of semen. It is only found in men and is located just below the bladder. Cancer of the prostate gland cause tumours to develop in the prostate, which becomes enlarged.
How many people are affected by prostate cancer each year?
According to Cancer Research UK, more than 27,000 men are diagnosed with prostate cancer every year.
According to the NHS Cancer Screening programmes, approximately 10,000 men die from the disease every year. This means that many men develop prostate cancer but do not die from it – in fact, only 1 in 25 men will die from the disease. This is because many forms of prostate cancer are slow-growing and the men can live out their lives without suffering any ill effects from the tumour.
What is the risk of developing prostate cancer?
The overall lifetime risk of developing prostate cancer for a man is one in 14. In other words 73 in every 1,000 men will develop prostate cancer in the whole of their lifetime.
However, age plays in important role: prostate cancer is largely a disease of older men. Men aged less than 50 years rarely develop prostate cancer, while half of all cases of prostate cancer are in men aged more than 75 years.
How is prostate cancer detected?
If it is suspected that there is a problem with your prostate, the following tests may be carried out.
Urine test – to look for blood in the urine or to see if the problems are due to an infection.
PSA blood test – a blood sample is tested for its level of prostate-specific antigen (PSA), a high level may suggest prostate cancer, however it may also be due to a less harmful cause.
Digital rectal examination – a urologist feels the prostate by inserting his or her finger into the back passage. The urologist can then feel for any abnormalities that may suggest prostate cancer.
However, none of these tests can confirm that a person has prostate cancer. For example, some men may have prostate cancer, but their PSA levels are normal. Meanwhile, two out of every three men who do have a raised PSA level do not have prostate cancer. Instead, their raised levels are due to either infection, exercise, sex or benign enlargement of the prostate (often known as BPH or benign prostatic hypertrophy).
The only way to confirm the presence of prostate cancer is to remove a section of the prostate and study it under the microscope – known as a biopsy. Even then it cannot be accurately known whether or not the cancer is slow-growing (and does not need treating) or is fast-growing (and should be treated).
For this reason, researchers are looking for a test that will accurately diagnose prostate cancer and show whether or not it is slow- or fast-growing.
What did the researchers find?
A gene, known as E2F3, plays an important role controlling cell division and growth. Overactivity of the E2F3 gene is thought to result in uncontrolled cell division and growth, leading to the development of a tumour. For this reason, the researchers decided to investigate whether or not E2F3 played a role in the development of prostate cancer.
The researchers found high levels of E2F3 activity in 98 out of 147 samples of prostate cancer (67 per cent). High levels of E2F3 activity are rarely found in samples of normal prostate tissue.
In addition, the researchers found that there was a significant association between high levels of E2F3 activity and the risk of death from prostate cancer. This suggests that increasing levels of E2F3 activity are associated with increasingly fast-growing cancers (also known as aggressive cancers).
Why is this important?
The findings suggest that it might be possible to develop a test for E2F3 activity that could help to diagnose whether or not a person has prostate cancer with greater accuracy than is currently possible.
Also, the findings suggest that such a test would be able to show whether or not the cancer was fast- or slow-growing.
Why is it important to find out how fast a prostate cancer is growing?
Because prostate cancer occurs in later life, many men with slow-growing prostate cancer can live out their natural lives without suffering any ill effects. They don’t need treatment. However, the aggressive form will shorten a man’s life and needs to be treated as soon as possible.
By being able to distinguish between the types of prostate cancer, many men will be spared treatment they did not need.
When will a test be available?
The researchers’ work is currently in the very early phases of development and it could be many years before a working test for the activity of E2F3 becomes available.