Most cancers arise from oncogenic changes in the genomes of somatic cells, and while the cells may migrate by metastasis, they remain within that single individual. Natural transmission of cancer cells from one individual to another has been observed in two distinctive cases in mammals (Tasmanian devils1 and dogs2,3), but these are generally considered to be rare exceptions in nature. The discovery of transmissible cancer in soft-shell clams (Mya arenaria)4 suggested that this phenomenon might be more widespread. Here we analyzed disseminated neoplasia in mussels (Mytilus trossulus), cockles (Cerastoderma edule), and golden carpet shell clams (Polititapes aureus) and found that neoplasias in all three species are attributable to independent transmissible cancer lineages. In mussels and cockles, the cancer lineages are derived from their respective host species, but unexpectedly, cancer cells in P. aureus are all derived from Venerupis corrugata, a different species living in the same geographic area. No cases of disseminated neoplasia have thus far been found in V. corrugata from the same region. These findings show that transmission of cancer cells in the marine environment is common in multiple species, that it has originated many times, and that while most transmissible cancers were found spreading within the species of origin, cross-species transmission of cancer cells can occur.

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BackgroundWe present an innovative approach to healthcare worker (HCW) training using mobile phones as a personal learning environment.Twenty physicians used individual Smartphones (Nokia N95 and iPhone), each equipped with a portable solar charger. Doctors worked in urban and peri-urban HIV/AIDS clinics in Peru, where almost 70% of the nation's HIV patients in need are on treatment. A set of 3D learning scenarios simulating interactive clinical cases was developed and adapted to the Smartphones for a continuing medical education program lasting 3 months. A mobile educational platform supporting learning events tracked participant learning progress. A discussion forum accessible via mobile connected participants to a group of HIV specialists available for back-up of the medical information. Learning outcomes were verified through mobile quizzes using multiple choice questions at the end of each module.MethodsIn December 2009, a mid-term evaluation was conducted, targeting both technical feasibility and user satisfaction. It also highlighted user perception of the program and the technical challenges encountered using mobile devices for lifelong learning.ResultsWith a response rate of 90% (18/20 questionnaires returned), the overall satisfaction of using mobile tools was generally greater for the iPhone. Access to Skype and Facebook, screen/keyboard size, and image quality were cited as more troublesome for the Nokia N95 compared to the iPhone.ConclusionsTraining, supervision and clinical mentoring of health workers are the cornerstone of the scaling up process of HIV/AIDS care in resource-limited settings (RLSs). Educational modules on mobile phones can give flexibility to HCWs for accessing learning content anywhere. However lack of softwares interoperability and the high investment cost for the Smartphones' purchase could represent a limitation to the wide spread use of such kind mLearning programs in RLSs.