SAN FRANCISCO -- Three new studies have shown promise in helping scientists use biological and genetic markers as early warning signs to help detect and treat certain cancers, Reuters quoted researchers as saying on Monday.

The studies, presented at the 93rd annual meeting of the American Association for Cancer Research, focused on so-called biomarkers for ovarian, breast, and head and neck cancers.

Biomarkers are biological or genetic signs in the blood or on chromosomes that can signal whether patients have cancer before symptoms arise, or if they have the ability to fight off certain forms of the disease. They can also help indicate whether some people may be genetically predisposed toward a specific cancer.

"It is likely that if we could use more biomarkers, it would lead to earlier diagnosis," Bin Ye, a researcher at Harvard Medical School, told the conference.

Ye and his colleagues used a high-tech screening process to identify the protein haptoglobin as a potential new biomarker for ovarian cancer -- a disease that kills an estimated 14,000 American women each year.

In the study, the researchers found evidence that higher levels of the protein made it more likely that a woman might contract ovarian cancer. This would be a step toward better detecting the disease and understanding the hard-to-fight-cancer, Ye said.

"The best chance to identify ovarian cancer at its earliest stages will come from developing more new markers and using them all in conjunction with traditional screening methods," he said.

Another new biomarker that could aid doctors and patients is the protein RHOC, which may signal small, invasive breast cancers that are likely to metastasize, according to researchers at the University of Michigan.

If the protein is validated as a marker, the test for it would be easy to incorporate in standard analyses because it can be done using procedures available even in small hospitals, University of Michigan researcher Celina Kleer said.

A separate German team found that a genetic mutation may lower survival chances for some patients with head and neck cancers -- a finding that could help develop a biomarker for diagnosis and a molecular target for therapy.

According to the researchers, the alteration is in the gene for the enzyme FGFR4, which is involved in control of cell growth. The mutation, called a single nucleotide polymorphism, changes one molecule at a specific location on the gene and leads to shorter survival rates.

"The mutation does not cause cancer but is associated with progression once the disease develops," said Axel Ullrich of the Max Planck Institute in Germany.