Un estudio multicéntrico permitió analizar los metabolitos volátiles de la piel sana y de la piel afectada con neoplasias cutáneas. Estos cambios en los compuestos volátiles está asociados con distintos perfiles de olor.
Futuros estudios dirigidos a la búsqueda de biomarcadores de enfermedades cutáneas permitirán distinguir diferentes trastornos de la piel como fotoenvejecimiento, cáncer, psoriasis, etc.
20 August 2008
Alan Mozes, HealthDay Reporter
(HealthDay News) — Researchers have identified an "odor profile" for skin cancer, with an eye toward developing a fast, simple and noninvasive test to diagnose the most common form of skin cancer in the United States.
"We found that the odor profile coming from the skin of skin cancer patients was markedly different than that coming from healthy skin," noted study author Michelle Gallagher, who conducted her research while a postdoctoral fellow at the Monell Chemical Senses Center in Philadelphia.
"So, we think that this kind of biomarker could be used in a rapid and noninvasive way to detect skin cancer," she said. "And this would be novel, because now the only way to do so is with a visual exam and a biopsy, which is, of course, invasive."
Gallagher presented the findings Wednesday at the American Chemical Society National Meeting & Exposition in Philadelphia.
Gallagher said that the specific chemical analysis she and her team used to explore odor profiling for skin cancer had not previously been attempted.
She noted, however, that other research teams have conducted work with dogs trained to detect skin cancers through smell.
Odor profiling has also been tested in the past to screen for other types of cancer. For example, the Cleveland Clinic announced in February that their investigators had successfully used an inexpensive breath sensor that detected lung cancer accurately in 75 percent of cases.
In all the research, scientists were able to differentiate healthy odor profiles from cancerous ones by picking up on the unique smells generated by the presence of differing amounts of naturally occurring chemicals known as volatile organic compounds (VOCs) in healthy versus diseased tissue.
In the current work, the authors first sampled the air above back and forearm areas among 25 healthy men and women between the ages of 19 and 80. Then, they tested the air above tumor sites in 11 basal cell carcinoma patients, as well as above the disease-free skin of 11 healthy volunteers.
The sampling revealed that cancerous tissue and healthy tissue contained different VOC "recipes," exuding different smells.
While skin cancer tissue did not produce any new VOCs, the diseased area had more of some chemicals and less of others.
The team hopes to develop an odor profile for each form of skin cancer, after which an attempt would be made to link the profiles to nano-sensor technology to fashion a kind of "electronic nose." The authors envision the resulting device as a kind of diagnostic wand, designed to sweep across the surface of the skin and detect cancer.
"This work is preliminary," said Gallagher. "But I think within a few years, it’s reasonable to say that this could end up being a diagnostic tool that would be a routine thing one could do in a doctor’s office. It’s a real possibility."
However, Dr. Jean-Claude Bystryn, former head of the melanoma program and vaccine clinic at New York University Medical Center, issued a word of caution.
"In terms of this replacing the standard method we have of diagnosing skin cancer, which is basically to look at a specimen under the microscope, it’s hard to imagine this would do it completely," he said. "Because when you’re dealing with cancer, the margin for error is really small. You don’t want to miss something that may be a cancer that then doesn’t get treated. And you don’t want to treat someone for cancer if they actually have something else. So, it’s really a very novel and interesting idea but one which I think really needs to be further researched and carefully confirmed."
20 August 2008
Our skin has an ‘odor profile’ and that knowledge may open doors to early and noninvasive skin cancer detection and diagnosis, say researchers at the Monell Center, who used odors from skin to identify basal cell carcinoma, the most common form of skin cancer.
Human skin produces numerous airborne chemical molecules known as volatile organic compounds, or VOCs, many of which are odorous. In the study presented at the ACS, the researchers obtained VOC profiles from basal cell carcinoma sites in 11 patients and compared them to profiles from similar skin sites in 11 healthy controls.
The researchers sampled air above basal cell tumors and found a different profile of chemical compounds compared to skin located at the same sites in healthy control subjects.
"Our findings may someday allow doctors to screen for and diagnose skin cancers at very early stages," said Michelle Gallagher, PhD.
Both profiles contained the same array of chemicals; the difference involved the amounts of specific chemicals â€“ some were increased and others decreased in samples from basal cell carcinoma sites.
The researchers plan to characterize skin odor profiles associated with other forms of skin cancer, including squamous cell carcinoma and melanoma, the most serious form of skin cancer.
To identify changes related to cancer, the researchers first needed to identify a normative profile for VOCs and to determine whether this profile varies as a function of age, gender or body site. In research published online last month in the British Journal of Dermatology, Gallagher and collaborators sampled air above two skin sites (forearm and upper back) in 25 healthy male and female subjects, who ranged in age from 19 to 79.
Using gas chromatography-mass spectrometry techniques, they identified almost 100 different chemical compounds coming from skin. The normative skin profile varied between the two body sites, with differences in both the types and concentrations of VOCs.
Aging did not influence the types of VOCs found in the profiles; however, certain chemicals were present in greater amounts in older versus younger subjects.
This work provides the first comprehensive characterization of skin volatile organic chemicals at sites other than the underarm in people of different ages and genders. Previous studies of human skin had used either male or female subjects and had only examined one skin area.
Implications of the research are wide-ranging. Together, the two studies may help advance development of new methods to analyze skin for signs of altered health status.
"Chemical biomarkers may eventually serve as objective clinical markers of disease if effective sensor technology can be developed," said Monell analytical organic chemist George Preti, PhD.
Increased understanding of the chemicals related to skin odor could also lead to development of more effective anti-aging skin care products.
Gallagher, a postdoctoral fellow in Preti’s laboratory at the time the research was done, currently is employed at Rohm and Haas, Spring House, PA.
Also contributing to the work presented at the ACS were Charles Wysocki and Jae Kwak (Monell Center), Steven S. Fakharzadeh and Christopher J. Miller (University of Pennsylvania School of Medicine), Andrew I. Spielman and Xuming Sun (New York University College of Dentistry) and Chrysalyne D. Schmults (Dana Farber/Brigham and Women’s Cancer Center).
Wysocki, Spielman, Sun, and James J. Leyden (University of Pennsylvania School of Medicine) contributed to research published in the British Journal of Dermatology.
This research was funded, in part, by the National Institutes of Health and by Ms. Bonnie Hunt.
Washington – El cáncer de piel libera un olor particular, determinaron químicos estadounidenses cuyos trabajos fueron divulgados hoy, lo que podría permitir la puesta a punto de una simple prueba de detección.
"Los investigadores sospechaban desde hace tiempo que olores emanaban de los tumores pero somos los primeros en identificar y en medir los componentes de estos olores", indicó Michelle Gallagher, principal autora de este estudio y química del Monell Chemical Senses Center de Filadelfia en Pensilvania.
El estudio debe ser presentado en la última conferencia anual de la American Chemical Society de Filadelfia.
"Este avance abre el camino a nuevos enfoques potenciales para diagnosticar el cáncer de la piel en base a un perfil de olores de la piel que, esperamos, conducirá a diagnósticos más rápidos y sin muestras", añadió Gallagher en un comunicado.
Para determinar si los olores de la piel cambiaban en las personas que sufrían cáncer de piel, esta científica junto a otros investigadores utilizaron técnicas avanzadas de cromatografía, un método de análisis físico-químico.
Este método les permitió analizar el aire que se encuentra justo encima de los tumores de 11 pacientes diagnosticados con un epitelioma basocelular, la forma más común de cáncer de piel.
Más de un millón de nuevos casos de este tipo de cáncer son diagnosticados cada año.
Los científicos esperan poder combinar su técnica con la tecnología emergente de los nanodetectores o "narices electrónicas" que permiten identificar productos químicos olorosos.
Michelle Gallagher piensa en la creación de una "nariz electrónica" que los médicos podrán pasar sobre la piel y que activará una alarma cuando "huela" la presencia de un cáncer.
Actualmente la medicina diagnostica el cáncer de piel practicando biopsias a las lesiones sospechosas, un procedimiento largo y doloroso.
Resumen del trabajo:
Analyses of volatile organic compounds from human skin.
Gallagher M, Wysocki CJ, Leyden JJ, Spielman AI, Sun X, Preti G.
Br J Dermatol. 2008 Jul 12
Background Human skin emits a variety of volatile metabolites, many of them odorous. Much previous work has focused upon chemical structure and biogenesis of metabolites produced in the axillae (underarms), which are a primary source of human body odour. Nonaxillary skin also harbours volatile metabolites, possibly with different biological origins than axillary odorants. Objectives To take inventory of the volatile organic compounds (VOCs) from the upper back and forearm skin, and assess their relative quantitative variation across 25 healthy subjects. Methods Two complementary sampling techniques were used to obtain comprehensive VOC profiles, viz., solid-phase microextraction and solvent extraction. Analyses were performed using both gas chromatography/mass spectrometry and gas chromatography with flame photometric detection. Results Nearly 100 compounds were identified, some of which varied with age. The VOC profiles of the upper back and forearm within a subject were, for the most part, similar, although there were notable differences. Conclusions The natural variation in nonaxillary skin odorants described in this study provides a baseline of compounds we have identified from both endogenous and exogenous sources. Although complex, the profiles of volatile constituents suggest that the two body locations share a considerable number of compounds, but both quantitative and qualitative differences are present. In addition, quantitative changes due to ageing are also present. These data may provide future investigators of skin VOCs with a baseline against which any abnormalities can be viewed in searching for biomarkers of skin diseases.