New imaging agent has an appetite for dangerous prostate tumors

Non-invasive imaging detects prostate cancer earlier than ever before, but can't accurately distinguish between malignant and benign disease. According to Lawson Health Research Institute's Drs. John Lewis and Len Luyt, a new molecular imaging probe could be the answer.

Ghrelin is a growth hormone produced by the stomach and pancreas to stimulate hunger. Malignant prostate cancer cells are known to consume it at much higher rates than normal prostate cells. The Lawson team believed this could be the key to singling out aggressive disease.

The Lawson team developed a ghrelin-based imaging agent, modifying the structure by decorating it with a fluorescent compound. Next, they tested it on samples from patients with prostate cancer. Results showed the signal was almost 5 times stronger in the malignant cancer cells than in normal prostate cells or benign cancer cells.

"Imaging tests such as PET or MRI are used to diagnose a number of cancers without biopsy, but biopsy is still the best option for prostate cancer," Dr. Lewis says. "This work suggests that imaging using ghrelin may allow us to perform a non-invasive biopsy to diagnose prostate cancer and potentially detect metastasis earlier."