Gao Y, et al. - In this secondary analysis of 10,649 organ transplant recipients, investigators analyzed the connection between HLA antigen mismatch and skin cancer incidence following a solid-organ transplant. Among heart and lung transplant recipients, HLA antigen mismatch seems to be related to decreased skin cancer risk following solid-organ transplant. The most statistically significant mismatch for skin cancer risk was the degree of HLA-DR mismatch, but not HLA-A or HLA-B mismatch. According to this retrospective cohort study, HLA antigen mismatch may activate tumor surveillance mechanisms in transplant recipients that protect against skin cancer and that the risk of skin cancer might be higher in patients receiving a well-matched organ.