Investigators

Melanoma is a deadly cancer when caught late yet is a surgically curable disease when detected and treated at the earliest stages. Fortunately, most melanomas begin on the skin, and thus we have the opportunity to detect them using visual examination. However, early detection of melanoma can be challenging even for the most experienced dermatologists. This can lead to failure to detect melanoma when it is most treatable or to a high rate of removal of benign lesions. Both increase health care costs and put patients at risk. My research focuses on new techniques to improve the early detection of cutaneous melanoma. Computer vision technology can be applied to the analysis of specialized images of pigmented skin lesions taken using a handheld instrument called a dermatoscope. We are studying ways to use the objective, analytical power of the computer to take a dermatoscopic image of a pigmented skin lesion and rapidly quantify features such as symmetry, size, and color distribution. The system can then compare a lesion that has not been biopsied to a database of images from lesions for which a diagnosis has been made using histopathology following removal (the gold standard for diagnosis of melanoma and other skin lesions) to aid the user in making a decision of whether or not to biopsy. In addition, I am interested in understanding which patients benefit most from screening for melanoma and have several publications that examine melanoma epidemiology, detection patterns, and associations between melanoma screening and outcomes.

The primary research interests of the Singh laboratory include molecular characterization of novel cancer chemopreventive agents and rational design of mechanism-driven combination chemoprevention regimens. Cellular and transgenic animal models are used to screen potential cancer chemopreventive constituents from dietary and medicinal plants. Cutting edge cellular, molecular biological, omics (metabolomics and proteomics), structural biology, and imaging techniques (MRI and bioluminescence) are used to (a) determine the mechanism of action of promising cancer chemopreventive agents, (b) monitor effects on cancer progression, and (c) identify biomarkers predictive of tissue exposure and possibly response. Some of the agents under active investigation in the Singh laboratory include: cruciferous vegetable-derived isothiocyanates, garlic-derived organosulides, and medicinal plant constituent withaferin A. As an example, recent published work from the Singh laboratory indicates suppression of glycolysis in mammary cancer prevention by withaferin A in a transgenic mouse model. Likewise, complementary cellular and molecular biological, targeted proteomics, and molecular modeling techniques were used to identify beta-tubulin as a novel target of cancer cell growth arrest by withaferin A (WA).

Dr. Yuan is a cancer epidemiologist with extensive experience in research on cancer etiology and prevention. Dr. Yuan is Principal Investigator of the Shanghai Cohort Study and the Singapore Chinese Health Study, two population-based prospective cohorts of more than 80,000 Chinese men and women with available baseline blood and urine samples with more than 25 years of active follow-up for cancer and other major health outcomes.

Utilizing these two large cohort resources coupled with a biomarker approach, Dr. Yuan and his research team have made several noteworthy contributions to the field of cancer epidemiology including (1) dietary aflatoxins as human hepatocarcinogens, (2) dietary isothiocyanates, a group of phytochemicals found in cruciferous vegetables, as potential chemopreventive agents against lung cancer development, and (3) urinary biomarkers of nicotine, tobacco-specific nitrosamines and polycyclic aromatic hydrocarbons as risk predictors for lung cancer in smokers.

Dr. Yuan also has extensive experience in designing and conducting randomized, double-blind intervention studies on cancer prevention. Dr. Yuan is leading the effort to conduct a randomized, double-blind phase II clinical trial to evaluate the effectiveness of dietary 2-phenethyl isothiocyanates (PEITC) supplementation on reduction of risk markers for lung cancer in smokers. In addition, Dr. Yuan, collaborating with Dr. Mindy Kurzer, his former colleague at the University of Minnesota, is conducting a randomized, double-blind phase II clinical trial to evaluate the efficacy of oral supplementation of green tea extracts (Polyphenon E) on reduction of risk markers for breast cancer in women.