show Abstracthide AbstractActinic keratoses (AK) arise in severely photo-damaged skin and, over time, can progress to squamous cell carcinomas (SCC). Both AK and SCC are common in Caucasian populations, and immunosuppressed organ transplant recipients have a markedly higher risk of developing SCC. This project compared the microbiomes of AK and SCC with control skin from a cohort of 32 transplant recipients, and with similar samples from immunocompetent subjects.