Spotting cancer sooner than ever before

February 1, 2010 7:21:06 PM PST
In the case of many cancers, early detection can mean the difference between life and death. Researchers at a center in the Bay Area are working on technologies they believe could spot cancer months and even years earlier than current tests.

Dr. Sam Gambhir with Stanford's Canary Center looks for cancer the way some people might study a weather report. He wants to know what is coming before it arrives.

"Things that we couldn't have detected before because they were too low a level of protein, because the tumor was so small, are now starting to be detectable in the blood," he said.

In his lab at the Canary Center, his research team is developing a new generation of tests designed to spot those cancers far earlier than current methods. By identifying proteins in the blood unique to cancer patients, researchers can then screen for these so-called biomarkers.

"Proteins, potentially in your tlood, that would be indicative of possible early cancer somewhere in your body; those would then be followed up by molecular imaging studies to actually image the sites of the cancer," said Gambhir.

To achieve that, the center is teaming with engineers at Stanford to refine an ultra-sensitive magnetic detection system able to spot these biomarkers in very low concentrations. It uses tiny metallic particles coated with antibodies which stick to the targeted proteins. A magnetic reader can then tell if the proteins are present in a blood sample and at what concentration.

"And the bottom line is that it's a thousand times better, more sensitive than the gold standard we have right now," said Don Listwin, a former tech executive who created the Canary Foundation after his mother's death from ovarian cancer. "Our stated goal is by 2015 to have tests in place for all solid tumors, so that means both the blood test and the imaging test."

Back in the lab, researchers are developing other imaging systems to pinpoint the size and location of the cancer. In one example, the movement in a mouse tumor is actually being produced by gas bubbles, also coated with antibodies, which stick to cancer cells and make them visible to ultrasound.

"Where doctors already use ultrasound to look at women in the abdomen and pelvis, we're marrying to bubbles that go and find the cancer, enhancing the ultrasound signal," said Gambhir.

Researchers believe they will ultimately be able to spot cancers months and even years earlier.

Scientists at the Canary Center say their first blood test, developed for ovarian cancer, is about to begin phase one clinical trials at Stanford. The first patient group will be women at high risk for ovarian cancer.