22. Ralph Steinman
Ralph Steinman is known for his work in the field of cancer research. Believing that dendritic cells could help activate immune cells and fight infections within the body, Steinman felt that the cells could be manipulated to combat cancer. When he was diagnosed with pancreatic cancer himself, he realized this was the time to prove that his research was valid.
In 2007, and with less than a 5% chance to live, Steinman launched a human trial on himself, using three different vaccines, experimental cell therapies, as well as chemo. While he ultimately died in 2011, he did live four years longer than doctors predicted.
Steinman would go on to win the Nobel Prize for his cancer research post-humously. His research has continued to help improve cancer treatments for patients across the globe to this day.