Comparison of Skin Cancer Incidence in Caucasian and Non-Caucasian Liver Vs. Lung Transplant Recipients: A Tale of Two Regimens.

BACKGROUND: Organ transplantation is a significant risk factor for the development of skin cancer. The impact of skin type, immunosuppressive regimens, and photosensitizing agents requires further study. OBJECTIVE: The objective of this study was to compare skin cancer development between Caucasian and non-Caucasian transplant recipients at the University of Southern California. METHODS: We performed a retrospective chart review of lung and liver transplantations to determine the incidence of post-transplant skin cancer. Participants included patients who underwent lung or liver transplantation between 2005 and 2013 at our institution. Patients included in the study were limited to those who survived through the study observation period. RESULTS: We analyzed 475 patients who underwent transplantation, including 370 liver transplant recipients and 105 lung transplant recipients. Among these, 46.3% identified as Caucasian, while 53.7% were non-Caucasian. Over a mean follow-up of 7.9 years, 11.8% of Caucasian patients developed at least one skin cancer, compared with 2.7% of non-Caucasians (p < 0.001). However, irrespective of race, skin cancer development was significantly greater in lung compared with liver transplant recipients (20.0% vs. 3.2%, p < 0.001). The standard immunosuppressive and prophylactic regimens were mycophenolate mofetil and tacrolimus based for both transplants. Mycophenolate mofetil was maintained throughout the course in lung transplant patients, whereas this agent was reduced and terminated when possible in liver transplant recipients. In addition, during the years examined, voriconazole, a known photosensitizing agent, was used in lung transplant recipients to prevent aspergillosis. CONCLUSIONS: Fair skin type increases post-transplant skin cancer development, irrespective of the immunosuppressive regimen. A higher risk of skin cancer is associated with different regimens; in particular photosensitizing agents may increase risk in transplant recipients.

Ontogeny of aerial righting and wing flapping in juvenile birds.

Mechanisms of aerial righting in juvenile chukar partridge (Alectoris chukar) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight.