Two new imaging agents may help physicians personalize cancer therapy and determine a patient's response to a drug 24 hours after it's administered.

These imaging agents can be used with PET and fluorescence imaging to visualize the formation of tumor-associated blood vessels and track tumor growth.

Researchers at the University of Alberta in Canada worked with colleagues at Western University and Case Western Reserve University to develop the imaging agents. They investigated a protein called EGFL7 that is specific to actively growing blood vessels.
The team started by creating peptides that attach to EGFL7 proteins in order to determine if they would be useful for imaging applications. PET exams using the peptide were performed on mice with tumors in order to localize the tumors and illuminate them.

They also used the peptide to create nanoparticles and those were shown to accumulate in the new blood vessels and illuminate as well.

Many cancer drugs on the market inhibit the formation of new tumor-related blood vessels, but it's difficult to determine which patients would benefit from them. They can be toxic for one patient and lifesaving for another.

The team believes that these new imaging agents can provide physicians with the information they need to make more personalized treatment decisions.

The agent can be used prior to treatment in order to see how many blood vessels are forming. That would determine whether an individual patient is a candidate for those drugs.

The agents can also be used during treatment to monitor their response to therapy. Traditionally, physicians measure changes in tumor size up to a month after treatment, but this new method could determine that in 24 hours.

The next step is to test the imaging agents in a treatment setting. The researchers will initially perform experiments on animal models and then move on to clinical work.

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