Early developing stage-specific liver proteins and the genes coding for them that have been isolated and sequenced are provided, and these genes and proteins can be utilized to diagnose and/or treat a wide variety of liver disorders and other ailments. Since the early developing liver proteins of the invention arise during embryogenesis when the liver and other organs are in transition from an undifferentiated state to a differentiated one, these proteins are involved in tissue differentiation and thus can be utilized in methods of diagnosing and treating a variety of liver diseases and other disorders including those relating to oncogenesis and tissue repair. Antibodies recognizing early developing liver proteins and peptides are also provided.