New prostate cancer marker
Prostate cancer is diagnosed in more than a million men every year, and the rates have more than doubled in recent decades...
Unlike cervical or breast cancer screening, which are well established in many countries and have a strong track record of success, there is no similar system system for prostate disease.
Part of the reason is that doctors lack a reliable "biomarker" that they can use to diagnose patients with prostate cancer, or find and follow their disease.
One marker that has been used in the past, PSA - prostate specific antigen - has a number of shortcomings: various processes other than cancer can change the level of the substance in the blood, and it doesn't reveal where in the body the signal is coming from, making metastatic disease (cancer that has spread) harder to pinpoint.
Now Johns Hopkins researcher Daniel Thorek and his colleagues, writing in Science Translational Medicine, have developed an antibody that solves many of these problems.
Called 11B6, it recognises a protein called hK2; this is produced exclusively within prostate cells. It can be injected into the bloodstream and is drawn into cells via a special uptake pathway. It's only then, within the cell, that it meets its hK2 target and binds.
By coupling the antibody to a label or marker molecule, it can be used to flag up prostate tissue, including cancerous cells that have spread to bones and other parts of the body. It could also be used to deliver therapeutic agents directly to tumours, by coupling a drug to it.
The antibody will ensure that the drug concentrates chiefly in prostatic cells, minimising side effects elsewhere in the body. So far the team have tested the antibody successfully in mice and now more recently in monkeys. A human clinical trial is planned for 2017.