Boston scientists believe they found stem cells in the lung that can make a wide variety of the organ's tissues.
Stem cells exist in bone marrow and other parts of the body. It hasn't been clear if the lungs also have the versatile cell.
Scientists are working to use stem cells as repair kits to fix damage from diseases like Parkinson's and diabetes.
As for the lung discovery, it's too soon to make any promises, but researchers say this could be a significant advance.
The work is reported in New England Journal of Medicine.