Browsing by Subject "Skin cancer"
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Item ASSESSING THE EFFECT OF KNOWLEDGE AND ATTITUDES ON SKIN CANCER PREVENTION IN RURAL COMMUNITIES(2013-05) Wang, Haiyan; Lyford, Conrad; Chidmi, Benaissa; Segarra, EduardoOne of the most common forms of cancer in the United States is skin cancer. Although the incidence of skin cancer is increasing annually, the distribution of skin cancer risk is not the same everywhere. Compared with urban residents, rural residents, who are typically older, less educated, and poorer than urban residents, have less access to early cancer detection programs and preventative health information. Yet almost all cases of skin cancer are preventable through appropriate protection from ultraviolet radiation. This study uses data from a project designed to prevent cancers caused by obesity, tobacco, and sunburn in rural communities. Data were collected from 382 randomly selected residents of two rural communities in Texas in 2011. The information collected included demographic characteristics, attitudes and behaviors regarding cancer prevention, general health knowledge and anthropometric measurements (height, weight, and waist circumference). Ordinal logistic regression analyses and Chi-square tests were used to examine the associations of factors affecting sunscreen use and sunburn frequency. This study found that rural residents, who are Hispanic, smokers, and obese were more likely to use sunscreen. Those who are obese, unmarried, and less educated were reported more frequently getting sunburned. Knowledge derived from this study can be used to determine the need and scope of future rural skin cancer risk intervention efforts. Rural residents need further public preventive interventions to protect present and future generations from skin cancer.Item Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis(2013-12) Lim, Liang; Tunnell, James W.The goal of this thesis is to study the potential of optical spectroscopy as a clinical diagnostic tool for melanoma and nonmelanoma skin cancer. Skin cancer is the most common cancer in the United States. Like most cancers, early diagnosis and treatment improves patient prognosis for both melanoma and nonmelanoma skin cancer. However, current “gold standard” for diagnosis is invasive, costly and time-consuming. A diagnostic procedure consists of a clinical examination of the suspicious lesion, followed by biopsy and histopathology, with an additional turnaround time of approximately one week. There is a need for an accurate, objective, noninvasive, and faster method to aid physician in diagnosing cancerous lesions, increasing diagnosis accuracy while preventing unnecessary biopsies. We propose Spectral Diagnosis, a system capable of noninvasive in vivo spectroscopic examination of human skin. The research objectives are: (1) Probe pressure effects on in vivo spectroscopy measurements of human skin, (2) Clinical trial of Spectral Diagnosis, (3) Design, construction, and characterization of a confocal Raman microspectroscope. Spectral Diagnosis utilizes an optical fiber probe that transmits and collects optical spectra in contact with the suspected lesion. We identified short term and light probe pressure effects to be minimal on diagnostic parameters, and should not negatively influence diagnostic performance. We conducted a clinical trial at the University of Texas MD Anderson Cancer Center, and our results show that principal components from three spectroscopy modalities (diffuse reflectance spectroscopy, laser induced fluorescence spectroscopy, and Raman spectroscopy) provide excellent melanoma and nonmelanoma skin cancer diagnosis. We also constructed and characterized a Raman microspectroscope, with the goal of developing a physiological-based fitting model to better understand the analysis of in vivo Raman spectroscopy data from human skin tissue.Item Mitochondrial uncoupling protein 3 blocks skin carcinogenesis and drives bulge stem cell differentiation and epidermal turnover(2009-05) Lago, Cory Ungles; Mills, Edward MichaelMalignant cells increase glycolysis and down regulate mitochondrial respiration for ATP production. Mechanisms for respiratory impairment in cancerous cells and their importance for carcinogenesis are not well defined. We found that expression of the respiration-inducing uncoupling protein 3 (UCP3) was normally expressed in murine skin and was greatly decreased in cutaneous malignancies. To better understand the significance of UCP3 in epidermal biology and to test the importance of respiratory changes in cancer development, we generated hemizygous mice expressing a keratin-5 promoter-UCP3 transgene (K5-UCP3). Compared to wild type, K5-UCP3 mice exhibited increased cutaneous mitochondrial respiration, had decreased mitochondrial membrane potential in isolated keratinocytes, and were completely resistant to chemically-induced skin carcinogenesis. We showed that the mechanism of UCP3-dependent cancer protection is most likely not due to increased intracellular heat production or ATP depletion in pre-cancerous cells. Therefore, because hair follicle "bulge" stem cells (bSC) are K5⁺ and progenitors of cutaneous carcinomas, we hypothesized that K5-UCP3 animals were protected from skin carcinogenesis due to alterations in their bSC population. Unlike WT, most (85%) hair follicle bulge regions in K5-UCP3 mice lost biochemical markers of quiescent bSC, but bSC functions were fully intact. Supporting our hypothesis that increased skin turnover protected K5-UCP3 mice from skin cancer; we showed that basal keratinocyte cell cycling was increased 3% in K5-UCP3 skin compared to WT. Moreover, the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) induced similar proliferative responses in both WT and K5-UCP3 skin, but the magnitude of TPA-induced skin thickening was greatly decreased in K5-UCP3 versus WT mice. Together with microarray, histochemical and in vitro morphologic analyses showing that keratinocyte differentiation was sharply increased in K5-UCP3 skin, this implies that UCP3 may increase keratinocyte transit from stem to differentiated daughter cells. Thus, the cancer resistance mechanism in K5-UCP3 mice likely stems from UCP3-induced mitochondrial respiration, which promotes the differentiation and abrogates the tumorigenicity of progenitor keratinocytes. This is the first demonstration in any context that UCP3 blocks carcinogenesis and promotes cellular differentiation. These observations support Warburg's contention that respiratory dysfunction promotes cancer development, and suggest that mitochondrial uncoupling may be a novel target for cancer prevention and treatment.Item Spectral diagnosis of skin cancer(2010-05) Rajaram, Narasimhan; Tunnell, James W.; Reichenberg, Jason S.; Nguyen, Tri H.; Dunn, Andrew K.; Milner, Thomas E.; Sokolov, Konstantin V.The number of skin cancer cases reported in the United States is increasing every year and nearly equals the total cancer cases detected from every other part of the body. Current detection strategies of skin cancers include a visual examination followed by a tissue biopsy. This procedure is subjective, invasive and time-consuming. Therefore, considering the number of cancer cases reported and the number biopsies performed, there is a critical need for a non-invasive diagnostic aid to help clinicians reduce the significantly large numbers of unnecessary biopsies. This dissertation presents a quantitative method based on optical spectroscopy for performing a non-invasive ‘optical biopsy’ of melanoma and non-melanoma skin cancers. We have developed the hardware, software and optical algorithms necessary to implement such a device. First, we present a novel lookup table-based model for determining the optical properties of tissue that is valid for fiber-based probe geometries with close source-detector separations and in highly absorbing tissue. These optical properties are quantitative parameters that can be correlated with the physiology of tissue. Second, we present experimental validation of the effects of microvasculature pigment packaging on diffuse reflectance spectra. We have conducted experiments using microfluidic devices over a physiologically relevant range of optical properties and blood vessel sizes. Third, we present the development of a probe-based portable and clinically compatible instrument capable of in vivo spectral measurements. The instrument combines two modalities – diffuse reflectance and intrinsic fluorescence spectroscopy – to provide complementary information regarding tissue morphology, function and biochemical composition. Finally, we present the results of a pilot clinical study using our portable instrument to determine the accuracy of spectral diagnosis of non-melanoma skin cancers. Our results show that the mean optical properties and fluorophore contributions of normal skin and non-melanoma skin cancers are significantly different from each other and can potentially be used as biomarkers for non-invasive diagnosis of skin cancer.