WASHINGTON (Reuters) - A protein that signals inflammation and heart disease may also show that a person has a high risk of cancer, researchers said on Friday.

People with high levels of C-reactive protein or CRP, already being studied for its links to heart disease, had a 30 percent higher risk of cancer, Danish researchers found. And cancer patients with the highest CRP levels were 80 percent more likely to die early, they found.

"These findings are preliminary and more research is needed to determine a precise link between CRP levels and cancer," said Dr. Eric Winer, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston.

"However, these findings support a possible link between inflammation and cancer, and the C-reactive protein test could one day be used to help select those patients who should be more frequently screened for cancer," Winer added in a statement released by the American Society of Clinical Oncology.

Dr. Kristine Allin and colleagues at the University of Copenhagen studied more than 10,000 people who had their CRP levels measured and then who were followed for 16 years.

About 1,600 developed cancer over this time and if they had high CRP levels at the beginning of the study, they were 30 percent more likely to be in this group of cancer patients.

And if a person both developed cancer and had high CRP levels, they were 80 percent more likely to die, whether from the cancer or something else, regardless of whether the cancer spread in their bodies, Allin's team reported in the Journal of Clinical Oncology.

Five years after cancer diagnosis, 40 percent of patients with high CRP levels were alive, compared with 70 percent of patients with low CRP levels.

CRP is associated with inflammation -- an activation of the immune system. It is not clear precisely if inflammation may cause heart disease and cancer, or if it is a symptom of the diseases, but some doctors are beginning to believe that measurements of CRP should be part of a regular health check.

"In addition to predicting heart disease risk, this simple test could help us assess a patient's future cancer risk and eventual cancer prognosis," Allin said in a statement.

(Reporting by Maggie Fox; Editing by Eric Walsh)

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