Complex sentence: Studies are underway to use and develop the dog as a model of this devastating disease of humans in the hope that characterizing and successfully treating these tumors in dogs may lead to improved therapies for humans afflicted with this disease.
Split into simpler sentences: Studies are underway to use and develop the dog as a model of this devastating disease of humans. It is thought that characterizing and successfully treating these tumors may lead to improved therapies for humans afflicted with this disease.