Scientists Work on Blood Test for Early Lung-Cancer Detection

Scientists are developing a blood test to detect lung cancer, one of the most common and deadly cancers in the world. The test, which looks for certain proteins in the blood, is designed to find tumors at their earliest, most treatable stage.

According to the World Health Organization, lung cancer is the leading cause of cancer death worldwide, claiming an estimated 1.5 million lives each year. The disease is caused mainly by cigarette smoking. Early detection followed by prompt treatment is essential to surviving this deadly, fast-growing cancer.

Researchers at the Fred Hutchinson Cancer Research Center in Seattle, Washington, report they have developed a new blood test for lung-cancer proteins. Those proteins are produced by tumor tissue early in the development of lung cancer and can be detected in plasma, a blood component that’s rich in proteins.

The scientists say the cancer test is so sensitive that it can detect the presence of markers or signatures that suggest tumor activity before they can be seen by advanced imaging devices such as a CT scan, which can spot tumors only a few millimeters across.

According to Sam Hanash, a scientist at Fred Hutchinson, and a lead researcher on the lung-cancer blood test, using CT scans to detect tiny tumors can save the lives of patients at risk of lung cancer.

But he says CT screening has a downside: A high percentage of its images reveal nodules that appear as potentially malignant tumors that necessitate surgery, but the tumors turn out to be benign. “And [there are] a lot of other potential complications, so there’s a need for a blood test so that we can make CT scans more reliable,” Hanash said.

Hanash says the lung-cancer blood test looks for protein signatures of the disease similar to the way other cancer blood tests work, including the CA 125 test for ovarian cancer and the prostate specific antigen, or PSA, test for prostate cancer.

In initial experiments with mice, Hanash and his colleagues discovered protein markers by switching on genes that gave the animals lung cancer and then switching off the cancer-causing genes.

Hanash says scientists next looked to see whether they could find the same cancer protein signatures in human lung-cancer cells.

“And the answer was ‘Yes!’ So that was pretty satisfying that in fact we’re not dealing with a curiosity type of finding that only mice seem to display, but we are dealing with a real feature of cancer cells whether mice-derived or human-derived,” Hanash said.

Hanash says researchers detected protein biomarkers unique to a number of different lung tumors as well as some of the molecular networks of genes that drive tumor development.

He says the next step is to develop a test that doctors can use with patients at risk for lung cancer, probably in about two years.

An article describing the development of a new diagnostic test for lung-cancer protein signatures is published in the journal Cancer Cell.