Complex sentence: He and Peyton Rous were awarded the 1966 Nobel Prize for Physiology or Medicine for discovering that hormones could be used to control the spread of some cancers, this was the first discovery that showed that cancer could be controlled by chemicals.
Split into simpler sentences: He and Peyton Rous were awarded the 1966 Nobel Prize for Physiology or Medicine for discovering that hormones could be used to control the spread of some cancers. This was the first discovery that showed that cancer could be controlled by chemicals.