Cancers and many other diseases often reveal themselves by the presence of proteins absent or inactive in people who do not suffer from such ailments. Researchers are finding new biomarkers, as they are called, at a rapid pace, and they promise faster, more reliable ways to detect a disease earlier and to determine the prospect of recovering from it.

To take advantage of these “hot” new sources of information, researchers at Harvard University have developed a cracker-size electric sensor boasting wires thousands of times thinner than a human hair. In the near future, such sensors might test people for cancer while they wait in their doctor’s office, or be implanted under their skin to monitor disease progression or the effectiveness of treatments.

“Our approach requires a minimum number of steps and very small samples [of blood],” says Charles Lieber, Hyman Professor of Chemistry, in whose lab the device was developed. “Tests done on human plasma samples show highly selective and unprecedented sensitivity to very small concentrations of protein markers that result from disease. The sensor detects multiple markers for the same or different diseases.

“These advantages lead to faster, possibly cheaper, and more reliable detection, which should greatly improve diagnosis and treatment of cancer and other complex diseases.”

Higher sensitivity should also lead to earlier detection. The sooner treatment starts for cancers, the better the chances for survival.

Higher reliability equals fewer mistakes, so-called “false positives,” that tell patients they have cancer or the AIDS virus when they do not.