Scientists Develop Novel Cancer Blood Test

A new blood test developed by Professor Amin I. Kassis of Harvard Medical School may be able to detect several different types of cancer far sooner and more accurately than current cancer screening methods allow.

The test is in early stages of development and will take at least five years to be ready for public use, Kassis said, although limited availability is possible in two years.

“It all depends on continued funding, although we are confident that the project will attract the necessary grants,” he said.

“We’ve been working on this test for two years now, and results from testing on laboratory mice have been very encouraging,” said Pichumani Balagurumoorthy, a research fellow in Kassis’ lab. While testing with human subjects has only just begun, Balagurumoorthy said, the first few of such tests have corroborated earlier findings.

“All existing blood tests for cancer are ineffective, with high false positives and false negatives,” Kassis said. “As a result, patients are prescribed inappropriate treatment.”

Kassis’ test looks to circulating tumor cells—any tumor, no matter how small, sheds tumor cells into the bloodstream. These cells typically die on their own, and are cleaned up by phagocytes—a type of white blood cell. The test examines whether markers of ingested tumor cells are detectable in the patient’s phagocytes. The results are then compared to an non-phagocytic white blood cells, such as lymphocytes. Kassis said that he conceived of this approach due to his background in immunology. While this field is typically far removed from radiology, he had a detailed knowledge of it from earlier in his career.

Tests so far have had a 100 percent rate of success; Kassis said that while both human and mice testing had proven unerring in detecting the right kind of cancer, early-detection has yet to be tested in humans.

Kassis has just returned from presenting the work at the annual meeting of the American Association of Cancer Research.

“The reaction was simply fabulous,” he said. “When you present an idea, people usually come to you with problems and objections. But when we showed them this test, everyone said, “this makes sense”. They were floored by its logical simplicity.”

S. James Adelstein, a professor of medical biophysics at HMS, said that while this is an exciting project, it is too early to assess its impact on the field.

“There have been only a few human tests, and while these have been encouraging, Dr. Kassis has so far only examined a small gene array,” he said.

Adelstein added that potential uses of the test include testing for cancer in patients who have previously suffered from it.