"Smelling" Skin Cancer: A Potential Tool for Detection and Diagnosis

Roxanne Nelson

August 21, 2008

August 21, 2008 — Specific skin-odor profiles can be used to identify basal-cell carcinoma, researchers reported at the American Chemical Society 236th National Meeting and Exposition. These findings may eventually translate into novel and effective methods of diagnosing not only basal-cell carcinoma, but also squamous-cell cancer and melanoma.

The researchers found a quantitative alteration of normal volatile organic compounds at the site of the carcinoma. Some of the compounds that they monitored were lower in relative concentration, as compared with normal skin, while others were increased.

Olfactory cues from breath or body odors have aided clinicians in making a differential diagnosis since the early days of medical practice. "And we've known for a long time that dogs are able to use their sense of smell to detect cancer in humans," said study author George Preti, PhD, a chemist with Monell Chemical Senses Center, in Philadelphia, Pennsylvania. "The first report about that was published in the Lancet in the late 1980s."

Subsequent studies have shown that dogs can smell the difference between people with both early- and late-stage lung and breast cancers and healthy controls and can detect both melanomas and bladder cancers. Since dogs are able to detect the presence of skin cancer via olfaction, this lent support to the hypothesis that cutaneous tumors produce a profile of volatile metabolites that differs from normal skin.

Dr. Preti and colleagues have been working on this research for more than 2 years, and to the best of their knowledge, this is the first time that investigators have examined the odors that emanate from the surface of both healthy and malignant skin and have used these particular techniques to identify the structures of the compounds present. They point out that while Italian researchers have recently published a study that utilized an electronic nose device to study melanoma tumor sites and healthy skin, their data did not identify which compounds differentiated malignant skin from healthy skin.

In this study, the researchers examined whether skin odors become altered in patients with basal-cell carcinoma. Their study cohort consisted of 11 patients with biopsy-confirmed basal-cell carcinoma, as well as controls matched for age, sex, and ethnicity. Odor samples were obtained by placing a glass funnel with an absorbent fiber over both the tumor sites and similar locations on the healthy controls. Solid-phase microextraction and gas chromatography/mass spectrometry were then used to investigate the profile of volatile organic compounds from both study groups.

When the data were reviewed, the researchers did not observe any obvious qualitative changes between malignant sites and control sites, but statistical analyses of the quantitative data suggested that in the cancer patients there were alterations in normal volatile organic compounds, as opposed to new ones related to the carcinoma. In other words, the researchers noted, the same compounds were present in both the cancer patients and controls, but in patients with skin cancer, some of the monitored compounds were reduced, while others were increased.

While this technology is promising and may eventually be useful as a diagnostic tool for basal-cell carcinoma and other skin cancers, Dr. Petri cautions that this is still basic research. "We are not anywhere near being able to use this clinically," he told Medscape Oncology. "But looking into possible future applications, this technology could be used to identify patients at high risk of skin cancers or to evaluate a suspected lesion if the patient wishes to avoid a biopsy."

The research was funded, in part, by the National Institutes of Health and by Ms. Bonnie Hunt.

American Chemical Society Annual Meeting: Abstract AGFD 227. Presented August 20, 2008.


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