In a groundbreaking new study, researchers from Wake Forest Baptist Medical Center have found high blood calcium levels might flag ovarian cancer — the most lethal of the gynecologic cancers.

The finding, published online in the journal Gynecologic Oncology, could point the way to a new way to predict women who may be at greater risk of developing ovarian cancer, which is often diagnosed late when it is harder to treat.

Lead researcher Gary G. Schwartz, a cancer epidemiologist at Wake Forest Baptist, made the connection by examining associations between blood calcium and ovarian cancer in two groups of cancer patients. Schwartz and co-researcher Halcyon G. Skinner, of the University of Wisconsin Carbone Cancer Center, found women who were later diagnosed with ovarian cancer and women who later died of ovarian cancer had higher levels of calcium in their blood than women who did not before their cancer diagnosis.

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Schwartz said the idea for this study sprung from earlier research that showed men with high calcium levels were at increased risk of aggressive prostate cancer. That led him to wonder if a similar relationship were true of ovarian cancer.

"One approach to cancer biomarker discovery is to identify a factor that is differentially expressed in individuals with and without cancer and to examine that factor's ability to detect cancer in an independent sample of individuals," Schwartz said.

"Everyone's got calcium and the body regulates it very tightly," Skinner added. "We know that some rare forms of ovarian cancer are associated with very high calcium, so it's worth considering whether more common ovarian cancers are associated with moderately high calcium."

The researchers explained that tumors in many cancers produce increased levels of a protein — known as PTRHrP (parathyroid hormone-related protein) — that raise calcium levels in blood.

The finding could be particularly significant for patients who develop types of cancer, such as ovarian cancer, that have high fatality rates because they are hard to detect early.

Schwartz said the findings could lead to the use of a calcium biomarker to diagnose ovarian cancer early, but noted more research is needed.

"We found the link between serum calcium and ovarian cancer; we confirmed it, and even though the study is small, we're reporting it because it's a very simple thing in theory to test," he said.

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