2016 Arte Poster Competition First Place Winner: Circadian Rhythm and UV-Induced Skin Damage: An In Vivo Study.

Exposure of the skin to ultraviolet (UV) irradiation causes many detrimental effects through mechanisms related to oxidative stress and DNA damage. Excessive oxidative stress can cause apoptosis and cellular dysfunction of epidermal cells leading to cellular senescence and connective tissue degradation. Direct and indirect damage to DNA predisposes the skin to cancer formation. Chronic UV exposure also leads to skin aging manifested as wrinkling, loss of skin tone, and decreased resilience. Fortunately, human skin has several natural mechanisms for combating UV-induced damage. The mechanisms operate on a diurnal rhythm, a cycle that repeats approximately every 24 hours. It is known that the circadian rhythm is involved in many skin physiologic processes, including water regulation and epidermal stem cell function. This study evaluated whether UV damage and the skin's natural mechanisms of inflammation and repair are also affected by circadian rhythm. We looked at UV-induced erythema on seven human subjects irradiated with simulated solar radiation in the morning (at 08:00 h) versus in the afternoon (at 16:00 h). Our data suggest that the same dose of UV radiation induces significantly more inflammation in the morning than in the afternoon. Changes in protein expression relevant to DNA damage, such as xeroderma pigmentosum, complementation group A (XPA), and cyclobutane pyrimidine dimers (CPD) from skin biopsies correlated with our clinical results. Both XPA and CPD levels were higher after the morning UV exposure compared with the afternoon exposure.

J Drugs Dermatol. 2016;15(9):1124-1130.

Epidemiology of genitourinary melanoma in the United States: 1992 through 2012.

BACKGROUND: Primary melanoma arising in the genitourinary tract is rare and poorly characterized. OBJECTIVES: We sought to describe the epidemiology of genitourinary melanoma in the United States. METHODS: Incident case and population data were obtained for genitourinary melanoma from the Surveillance, Epidemiology, and End Results 13 Registries Database between 1992 and 2012. RESULTS: A total of 817 patients with genitourinary melanoma were identified; most cases occurred in the vulva. The incidence of genitourinary melanoma was much higher in women (1.74/1 million person-years) than men (0.17/1 million person-years). The highest rates occurred among non-Hispanic white women aged 85 years and older. Five-year melanoma-specific and overall survival were poor at 52.4% and 36.3%, respectively. Predictors of poor survival were increasing age, black race, and female sex. LIMITATIONS: The study population is small, therefore some rates reported may be unstable. In addition, cutaneous, mucosal, and other extracutaneous surfaces of the genitourinary tract cannot be reliably distinguished in Surveillance, Epidemiology, and End Results. Furthermore, melanomas may be underreported to cancer registries. CONCLUSION: From 1992 to 2012, genitourinary melanoma was 10 times more common in women than men. Survival was poor in women compared with men, which is different from cutaneous melanoma where women have a survival advantage.

Cutaneous manifestations associated with melanoma.

Melanoma is a malignancy most commonly arising from the skin; therefore, primary melanoma characteristics are usually the first cutaneous manifestations of melanoma. Cutaneous metastases, which can occur locally or diffusely, are important to detect in a timely manner as treatments for advanced melanoma that impact survival are now available. Melanoma can be associated with local or diffuse pigmentation changes, including depigmentation associated with the leukodermas and hyperpigmentation associated with diffuse melanosis cutis. The leukodermas occur frequently, illustrate the immunogenic nature of melanoma, and may impact prognosis. Paraneoplastic syndromes in association with melanoma are rare, though can occur.