Sensor Hones Into Odor Emitting Cancer Sites

Imagine detecting skin cancer at a very early stage merely by using a sensor with an alarm that sounds when it detects abnormal variations in volatile chemical odors in the patient's skin.

Although still in the prototype stage, researchers proved the technology works with basal cell carcinoma, and plan to soon assess efficacy for early detection of melanoma and squamous cell cancers as well.

"It's very promising. There are volatiles present that are indicative of cancer. They are present in normal and cancerous skin, but levels change in a quantitative manner," said George Preti, Ph.D.

Using gas chromatography and mass spectrometry, Dr. Preti and his associates demonstrated that basal cell carcinoma lesions in 11 people emitted different levels of volatile organic skin chemicals, compared with noncancerous skin, in 11 controls. They found many of the chemicals to be odorous. Coauthor Michelle Gallagher, Ph.D., presented their findings at the annual meeting of the American Chemical Society. Specific chemical identities have not been released.

The current study builds on previous research done by Dr. Gallagher and her associates.

In a report, they identified nearly 100 different chemical compounds normally emitted by the forearm and upper back of 25 healthy volunteers (Brit. J. Derm. 2008 July 12; [doi: 10.1111/j.1365–2133.2008. 08748.x]). The study included patients aged 19–79 years and found some changes in skin emissions with age.

Other reports are anecdotal or only evaluate skin odor differences at the underarm (J. Chem. Ecol. 2005;31:1607–19; Chem. Biodivers. 2004;1:2042–50). The researchers began assessing skin emissions after studies showed that dogs were able to identify people with early-stage cancers using their heightened sense of smell (Integr. Cancer. Ther. 2006;5:30–9; BMJ 2004;329:712).

This was a proof-of-principle study, said Dr. Preti, who estimated clinical availability could take 7–10 years. He and his colleagues used a volatile organic chemical sensor designed for industrial and other applications, and next plan to design a probe specific to human skin.

Dr. Preti is a member of the Monell Chemical Senses Center, a nonprofit institute in Philadelphia. Dr. Gallagher was a postdoctorate fellow in Dr. Preti's lab at the time of the study; she is now at Rohm and Haas in Spring House, Pa. The authors of the study had no relevant financial disclosures.