Certain Prostate Cancer Tumors More Likely to Metastasize

Certain prostate tumors have the potential to become metastatic if not treated aggressively, according to new research from Dana-Farber Cancer Institute.

These tumors carry four molecular markers and increase chances of becoming dangerously metastatic. This discovery lays the groundwork for a gene-based test that could help predict whether prostate cancer will remain confined or spread (and therefore need aggressive treatment).

The standard measure of aggressiveness in prostate cancer, known as the Gleason score, is based on the number of cancer cells appearing under a microscope and is accurate 60 percent to 70 percent of the time. Looking at whether the tumors carry the four gene "signature" proved accurate 83 percent of the time. Combining the two testing methods allowed for approximately 90 percent accuracy.

Researchers found about 300 genes that distinguished between indolent and aggressive mouse prostate cancers and categorized them for known functions, according to study leader Ronald DePinho, MD. They deduced a four-gene signature comprised of the proteins Pten, Smad4, SPP1, and CyclinD1, which showed effectiveness as a predictive tool for survival.

According to DePinho, approximately 48 men are treated for prostate cancer for every life saved, resulting in overtreatment costing more than an estimated $600 million in the United States every year in addition to the physical tolls of radiation and surgery treatments.

A lack of uniformity among cancer cells in different prostate tumors has so far been a major obstacle in developing better prognostic tools as it has previously been difficult to identify genes that accurately indicate a tumor's potential to metastasize.

After skin cancer, prostate cancer is the most common cancer in men with about 217,730 new cases estimated to have been diagnosed last year.