has been used as an animal model for human lung cancer, because OPA is histologically similar to human adenocarcinoma in situ of the lung. Society and culture Dolly the sheep, the first mammal successfully cloned from an adult somatic cell, was euthanized after it was confirmed that she had OPA. See also Enzootic nasal adenocarcinoma Jaagsiekte sheep retrovirus Enzootic nasal tumor virus References Sheep and goat diseases Animal viral diseases