An artificial electronic “nose” that uses nanomaterials to recognize patterns of molecules in exhaled breath was able to distinguish between patients with head and neck or lung cancer and healthy controls, according to a study by researchers in Israel published by the British Journal of Cancer this week.

The Nanoscale Artificial Nose (NA-NOSE) was developed by senior author of the study, Professor H Haick, and his group at Technion, the Israel Institute of Technology in Haifa. They hope the results of their study will lead to the development of a fast, reliable and cost-effective tool for the differential diagnosis of head and neck cancer, and possibly also a screening tool, based on the artificial nose.

Head and neck cancer is a group of cancers that affect the lip, the mouth, the nasal cavity, sinuses, salivary glands, pharynx and larynx. It is the eighth most common cancer in the world, and in the US for example, it accounts for between 3 and 5% of all cancers.

Head and neck cancer is often diagnosed late, because of a lack of screening methods. Patients treated for head and neck cancer are also at higher risk of developing a new cancer in their aero-digestive tract, usually in the head and neck, esophagus, or lungs, so they need to have regular checkups for life.

NA-NOSE uses an array of five gold nanoparticle sensors and computer algorithms to detect patterns of volatile organic compounds in exhaled breath.

Because of the small size of the nanoparticle sensors, thousands of times smaller than the thickness of human hair, a few molecules are enough to change the electrical properties of their material, which in the case of the NA-NOSE is based on gold and platinum “functionalized” with organic ligands customized to sense particular organic compounds.

According to Technion, their nanoparticle sensors are up to 1,000 times more sensitive and respond much faster, than most of the current state of the art sensors. They are also designed to sense low concentrations of compounds, which is very important since exhaled breath is over 80% water vapor.

For this study, which they designed as a cross-sectional clinical trial (where you measure one or more variables at one point in time and compare values across groups) the researchers collected exhaled breath from over 80 volunteers, comprising patients with head and neck cancer, patients with lung cancer, and healthy controls.

Using analytical tools, they measured statistically significant differences among the chemical compositions that the artificial nose detected in 62 of the samples.

The researchers said that their artificial nose could “clearly distinguish” between:

  • Head and neck cancer patients and healthy controls,
  • Lung cancer patients and healthy controls, and
  • Head and neck cancer patients and lung cancer patients.

A separate analysis of 40 breath sample using gas chromatography and mass spectrometry analyses also showed statistically significant differences in the chemical compostion of the exhaled breath of the three groups, supporting the artificial nose results.

Haick and colleagues concluded that:

“The presented results could lead to the development of a cost-effective, fast, and reliable method for the differential diagnosis of HNC [head and neck cancer] that is based on breath testing with an NA-NOSE, with a future potential as screening tool.”

Haick said they now need to replicate these results in larger studies, to test the feasibility of developing the NA-NOSE as a diagnostic and screening tool, reports the BBC.

Although it is likely to be many years before we see the artificial nose in a clinical setting, the study’s findings appear to offer a promising starting point for the development of a straightforward breath test for head and neck cancer.

“Diagnosis of head-and-neck cancer from exhaled breath.”
M Hakim, S Billan, U Tisch, G Peng, I Dvrokind, O Marom, R Abdah-Bortnyak, A Kuten and H Haick.
Br J Cancer advance online publication, 19 April 2011

Additional sources: Technion LNBD, NCI, BBC News.

Written by: Catharine Paddock, PhD