Scent of skin cancer may help early detection
CTV.ca News Staff
Published Thursday, August 21, 2008 1:29PM EDT
It's long been known that some dogs can sniff out cancer in humans. Now chemists believe they can identify skin "odour profiles" that could help with early and non-invasive skin cancer detection.
The findings, reported Thursday at the 236th national meeting of the American Chemical Society, may allow doctors to diagnose skin cancer earlier, faster and more accurately by waving a scanner across the skin.
The study suggests that odours from the skin can be used to identify basal cell carcinoma, the most common form of skin cancer.
"What researchers did was sample the air above basal cell tumours and found a different profile of chemical compounds compared to skin located in the same area in healthy subjects," CTV Health reporter Marni Kuhlmann told CTV Newsnet. "They hope that this finding may someday allow doctors to screen for and diagnose skin cancers at very early stages."
In the new study, Michelle Gallagher, Ph.D., and her colleagues point out that scientists demonstrated that dogs can be trained to detect skin tumors because the tumours have a different smell than normal skin, stated a press release.
By building on that idea, researchers found that the skin of people with skin cancer releases a different odour profile than that of people without the disease.
Gallagher and colleagues used advanced chromatography techniques to sample and analyze the air above tumour sites in 11 patients. They compared their findings to the skin of 11 people without cancer.
"The same chemicals are present, but at skin cancer sites some chemicals are increased, while others are decreased compared to healthy individuals," said Gallagher in a press release.
The scientists eventually plan to come up with a reliable "odour profile" for all forms of skin cancer. If successful, the researchers hope to combine their method with new nano-sensor or "electronic nose" technology, which was designed to identify chemical scents. Gallagher says one day a wand-like "E-nose" could be moved across the skin and set off an alarm when cancer is detected.
Dogs can detect the presence of skin cancer via olfaction, supporting the hypothesis that skin tumors produce a different profile of volatile metabolites than normal skin. We used solid-phase microextraction and gas chromatography/mass spectrometry (GC/MS) to investigate the profile of volatiles from individuals with basal cell carcinoma (BCC) tumor sites, as well as similar sites from the control subjects. Inspection of GC/MS data demonstrated no obvious qualitative changes between BCC sites and control sites. Several compounds chosen because of their structure, origin and/or biogenesis were monitored in a quantitative fashion in all patients and controls. Statistical analyses of the quantitative data suggest that rather than "new" volatile organic compounds (VOCs) related to the carcinoma, we see a quantitative alteration of the normal VOC profile at the BCC site: some of the monitored compounds decrease, and others increase in relative concentration. Supported by NIH (Training grant #: T 32 DC00014-26) and Ms. Bonnie Hunt.
Researcher Provided Non-Technical Summary
The skin naturally produces organic chemicals, many of which have an associated odor. To examine whether skin odors change in individuals with skin cancer, we sampled the air above tumor sites in individuals diagnosed with basal cell carcinoma and compared the profile of organic chemicals to that above the skin at similar body sites in healthy controls. We found a different profile of chemicals above tumor sites relative to healthy skin; the same chemicals are present, but at skin cancer sites some chemicals are increased, while others are decreased compared to healthy individuals. Skin cancer is the most common form of cancer in the United States. Early diagnosis is closely linked with a positive prognosis. Currently, early detection of skin cancer is accomplished primarily through a visual exam, followed by imaging and/or biopsy of any suspected areas. This research opens doors to potential new approaches to skin cancer diagnosis based on the profile of skin odors, hopefully leading to more rapid and non-invasive detection and diagnosis of this prevalent disease.
How new is this work and how does it differ from that of others who may be doing similar research?
We have been working on this research for over two years. To the best of our knowledge, no other researchers have examined the odors emanating from the skin surface of healthy and malignant skin using either the techniques we employed or identifying the structures of the compounds present.
An Italian group recently published work using an electronic nose device to study melanoma tumors sites and healthy skin. They did not identify which compounds differentiate healthy from cancerous skin.
Lead presenter: Michelle Gallagher, with George Preti, Steve Fakharzadeh, Charles J. Wysocki, Jae Kwak, Christopher J. Miller, Chrysalyne D. Schmults, Andrew I Spielman, and Xuming Sun.