A low-cost electronic "nose" designed to detect stomach cancer molecules in the breath can also spot signatures of lesions that herald the disease.

The Israeli-designed tester uses gold nano-particles to detect so-called volatile organic compounds that are a tiny telltale in the breath of cancer patients.

In a study published on Monday in the journal Gut, the nano-array device was compared against the benchmark for VOC assessment - a more complex and expensive lab technique using gas chromatography and mass spectrometry.

Each method was used to screen breath samples taken from 484 volunteers in Latvia, 99 of whom had already been diagnosed with stomach cancer but had not yet been treated for it.

Both methods accurately spotting those with the cancer, as well as the "breath prints" of high-risk patients who had lesions that often develop into gastric tumours.

The research - published in a peer-reviewed journal - was led by Hossam Haick, a professor at the Israel Institute of Technology where the nano-array was developed.

Cancer specialists are interested in VOC testers because they offer the possibility of non-invasive screening for a disease that, tragically, is often spotted too late.

A device that would be cheap, portable and also pinpoint precursor conditions would be especially welcome.

For patients with suspected stomach cancer, a useful breath test would avoid the discomfort of an endoscopy, saving the resource for those who need it.

The problem, though, is to overcome concern about accuracy - the telltale amounts are only 10 particles per billion or less in a sample of exhaled breath.

In an independent comment, French gastro-enterologist Jean-Christophe Saurin of the University Hospital Centre in Lyon urged caution.

"More tests are needed" to prove the nano-array's accuracy, he said.

Trials should also confirm whether a precursor condition actually developed into cancer, in order to avoid unnecessary treatment, he told AFP.