U.S. researchers have discovered specific changes in the blood of patients with two deadly cancers that may allow doctors to diagnose them at an earlier stage.

Using new screening technology developed by privately held Somalogic Inc, company researchers said on Tuesday they could detect early signs of pancreatic cancer and a type of lung cancer called mesothelioma in people who had been diagnosed but not treated for the diseases.

Currently these cancers are detected at an advanced stage, where the possibility of cure is minimal, said Rachel Ostroff, clinical research director of Somalogic Inc, who presented the findings on Tuesday at an American Association for Cancer Research meeting in Denver.

Detection of these aggressive cancers at an earlier stage would identify patients for early treatment, which may improve their survival and quality of life.

Pancreatic cancer is relatively rare, but it is the fourth-leading cause of cancer-related death in the United States. Mesothelioma, caused by asbestos, kills an estimated 15,000 to 20,000 people per year worldwide.

In August, NEC Corp of Japan invested $5 million as part of a strategic partnership with Colorado-based Somalogic to develop the technology, which aims to detect disease by examining proteins in a drop of blood.

Somalogic's tests rely on aptamers -- bits of genetic material that stick to proteins. Somalogic has refined a technology that makes these molecules more likely to cling to specific proteins.

For the study, company researchers tested blood samples of patients with both cancers and those in control groups who had conditions that gave them symptoms similar to these cancers, such as pancreatitis or lung fibrosis.

The team used computer modeling to look for significant biological differences, or biomarkers, that distinguished blood samples of cancer patients from those without cancer.

For both cancers, the team found biological markers that were highly accurate in detecting each type of cancer, Ostroff said. They were also highly specific, meaning they were able to correctly rule out people who did not have those cancers.

Now the biomarkers need to be confirmed in other studies to ensure the results were accurate and can be reliably reproduced in diagnostic tests. It's very easy to discover biomarkers, Ostroff told the meeting. It is very hard to validate them.

Ostroff said her team will look at several factors that could lead to false positive results, such as how long a sample has been sitting on a shelf before it was tested.

We'll look at enough of these parameters to make sure we are looking at disease biomarkers, she said.

Japan Medicine Cancer