Growth factor predicts cancer's spread.

Ancient physicians would hold a flask of urine to the light, turning it this way and that in search of signs of disease. Modern researchers are perfecting a more sophisticated version of that test, homing in on urinary concentrations of a growth factor involved in cancer's deadly spread.

Researchers had previously demonstrated that a peptide called basic fibroblast growth factor could trigger the beneficial growth of vessels supplying the heart with blood (SN: 1/29/94, p.71). The dark side of this growth factor, and others like it, is that they also boost a tumor's blood supply, thus enabling it to grow and metastasize to distant parts of the body.

Now, a simple test that measures the concentration of basic fibroblast growth factor in the urine may indicate a cancer's aggressiveness, according to a new study by Judah Folkman of Harvard Medical School in Boston and his colleagues,

Folkman and his team knew from their previous work that basic fibroblast growth factor predicts the extent of bladder cancer, but they wanted to find out whether the peptide could do the same for other types of cancer. They therefore analyzed urine samples collected from 950 people with a range of malignancies (including cancers of the breast, colon, and lung) and 285 controls who did not suffer from cancer of any kind.

The team found elevated concentrations of the growth factor in the urine of some cancer patients in every category except cervical cancer. "This is the first demonstration that a wide variety of tumors produced abnormally high levels of basic fibroblast growth factor," Folkman told SCIENCE NEWS. The researchers describe their work in the March 2 JOURNAL OF THE NATIONAL CANCER INSTITUTE.

Compared to controls or cancer patients whose disease had not spread, people with cancer that had migrated to other parts of their body had the highest concentrations of growth factor in their urine samples,

The team monitored a subset of cancer patients after an operation had been performed to remove their primary tumor. People whose tumor had not metastasized showed normal urinary concentrations of growth factor within a short time after surgery. By contrast, people whose cancer showed evidence of advancing continued to demonstrate elevated amounts of growth factor in repeated urine tests.

If further research confirms these findings, oncologists may one day rely on this urine test to gauge a cancer's severity. "In a patient with a known tumor, you could use the urine to monitor whether or not that tumor progresses," comments Anton Wellstein of Georgetown University in Washington, D.C. If such a test indicates that the cancer continues to spread after the initial treatment, oncologists could rev up treatment, says Wellstein, who wrote an editorial that appears in the same issue of the journal.

Use of this test as a general screen for cancer appears less likely, Wellstein says, noting that cancers in their early stages probably don't release enough of this peptide to be identified.