Nakajima et al. showed that adenosine deaminase (ADA), an enzyme that catalyzes the deamination of adenosine to inosine and deoxyadenosine to deoxyinosine, is increased in MPM pleural effusions compared to benign diseases, suggesting the existence of an endogenous mechanism able to switch-off ADO signaling [134]. This evidence concerns the gene ADA and Pleural effusion.