Hitting Prostate Cancer Before It Spreads

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One in seven men will get hit with prostate cancer, that's the Bad News. If there is any Good News to be found, it's that the cancer in only about 20 percent of those men will develop into a life-threatening tumor requiring aggressive treatment. The trick has ever been to differentiate clinically significant, high-risk tumors that need treatment from those low-risk tumors that do not require treatment. It's a trick we're slowly getting better at performing.

Take as Exhibit 'A' a new peptide engineered by the National Institute of Biomedical Imaging and Bioengineering. It has been designed to bind to a protein found in high-risk prostate cancers. When that peptide is linked to a clinically used magnetic resonance imaging (MRI) contrast agent, it serves to identify aggressive, metastatic tumors in mouse models of prostate cancer.

The scientists created a synthetic peptide, dubbed ZD2, that binds to the cancer-causing oncoprotein ED8-FN. This protein is only expressed by aggressive prostate cancer cells that are resistant to chemotherapy and metastasize through through surrounding tissues. In other words, the breed of prostate cancer you want to identify as quickly as possible.

The researchers put a bell around the neck of their synthetic peptide, in the form of an attached contrast agent with magnetic properties that cause it to produce a strong signal detectable by MRI.

Senior author Zheng-Rong Lu noted that, “Not only does ZD2-Gd bind specifically to the high-grade prostate cancer cells, but it binds so well that it can detect even early stage tumors of small numbers of these cells. This means we can potentially use MRI to non-invasively find those individuals with the high-grade tumors and find them early when treatment has a much higher chance of being effective.”

Lu and his colleagues are hopeful that their synthetic peptide has real potential as a solution for non-invasively determining which men have aggressive cancers in need of treatment, and which have slow-growing tumors and can avoid unnecessary invasive treatments. It is worth noting that the system could also be used to routinely and non-invasively monitor the slow-growing group for any changes in the aggressiveness of their tumors over time.

The research has been published in Bioconjugate Chemistry.