John von NeumannJohn von Neumann was one of the most versatile and brilliant mathematicians of all time.  He was diagnosed with prostate cancer in 1955 and died a year later after it spread quickly to his bones and brain.  He had helped to develop both atomic and hydrogen bombs and was exposed to radioactivity while observing A-bomb tests in the Pacific and while working on nuclear weapons at Los Alamos, New Mexico.  His close friend and fellow nuclear pioneer, Enrico Fermi, died of stomach cancer in 1954.  Von Neumann's cancer caused such unmitigated bone pain that he screamed constantly in his final days, yet he was able to recite Goethe's Faust from memory.  The U.S. Army stationed military guards outside his hospital room at Walter Reed Medical Center because of concern that he might reveal military secrets as he babbled in Hungarian and other languages under the influence of pain medications.
Von Neumann made major discoveries in more different fields of mathematics than any other mathematician in history. During World War II, he was the person most responsible for the method used to detonate the atom bomb. After the war, he started the whole computer revolution and his breakthroughs lead to construction of the first stored-program computer. He worked with Allan Turing to make modern computers more efficient in storing programs and data, and he was one of the first people to use computers to solve problems with complex mathematical equations.  He established Game Theory, developed computer games, defined ordinal numbers mathematically, was one of the first to explain quantum mechanics, and developed what is known as Minimax Theory. He was in charge of the world's first numerical weather forecasts on his ENIAC computer. His mathematical analysis of the structure of self-replication was directly responsible for the discovery of the structure of DNA. 
He had such an incredible photographic memory and could solve problems in his head at such dazzling speed that Nobel Laureate Hans Bethe said, "I have sometimes wondered whether a brain like von Neumann's does not indicate a species superior to that of man". During the building of the atom bomb, other scientists in the Manhattan Project joked that the Hungarians (von Neumann, Edward Teller, Leo Szilárd, John Kemény and others) were so smart that they couldn't be humans and therefore must be Martians and they spoke Hungarian as a cover.
Brilliant from Birth
Von Neumann was born in 1903 to wealthy Hungarian Jewish parents. His father, Max Neumann, must have been an extraordinary individual because he moved from the segregated Jewish community in Pecs to the cosmopolitan city of Budapest where he earned a doctorate of laws degree and became a banker. In 1913, Emperor Franz Josef appointed him to the nobility for his service to the Austro-Hungarian Empire, and the family name eventually was changed from Neumann to von Neumann. 
He was schooled by private tutors and by age seven, in addition to his native Hungarian, he was fluent in Latin, ancient Greek, French and German. He loved ancient history. By age eight he had mastered calculus. At age 22, he received his Ph.D. in mathematics (with minors in physics and chemistry) from Pázmány Péter University in Budapest. At the same time he received a degree in chemical engineering in Zurich. From 1926 to 1930, he became the youngest person ever to teach at the University of Berlin and produced a major paper nearly every month. 
In 1930 he went to Princeton University and three years later, at age 29, he was appointed to the Institute for Advanced Study, where he worked with Albert Einstein and Oswald Veblen. He consulted on the building of the atomic bomb in Los Alamos and developed the technique used to detonate the bomb. Two of the geniuses who worked closely with him on the atomic bomb  later became professors at Harvard, where I was able to take courses in the complex variable with Garrett Birkhoff and physical chemistry with George Kistiakowsky.
On July 16, 1945, von Neumann watched the explosion of the first atomic bomb in Socorro, New Mexico. He loved the United States and hated fascism and communism. He served as a member of the United States Atomic Energy Commission from 1953 until his death in 1957. He also consulted for the Central Intelligence Agency, the United States Army, the RAND Corporation, Standard Oil, General Electric and IBM.
A Personal Life of Excess
In 1929 at age 26, he married Marietta Kovesi, a brilliant economics student and wealthy social butterfly at the University of Budapest.  In 1936, they had a daughter, Marina, who was also brilliant, and became an economics professor at the University of Michigan and a vice president and chief economist at General Motors.  In 1937, he and his wife divorced and in 1938, he married Klara Dan, a twice-divorced Hungarian genius who became one of the world's first computer programmers, writing code to solve difficult mathematical problems on computers. At age 14, she had won the Hungarian national championship in ladies’ figure skating. At their home, the largest house in the Institute for Advanced Study at Princeton, the von Neumanns hosted long and wild parties that are still talked about today.  Their neighbors such as Albert Einstein complained about the extremely loud German marching music they played on their gramophone. Von Neumann was gregarious, told jokes all the time, often drank more than he should but could still solve complicated mathematical problems while drunk. He often overate and was quite obese in his later years.  He did whatever he wanted to do, read books while driving a car, received numerous traffic tickets and had several serious traffic accidents.  
Did Exposure to Radiation Cause his Cancer?
Von Neumann's many biographies list prostate, pancreatic, bone and brain cancers as the causes of his death. Cancer does not kill just because it is cancer; it kills by destroying other tissues.  Prostate cancer does not kill when the cancer is in the prostate; it kills when it spreads from the prostate to the brain, liver, lungs, bones or other vital tissues and destroys them. 
Excessive exposure to radiation is a strong risk factor for many types of cancers. Von Neumann was present at nuclear tests both at Los Alamos and at the Operation Crossroads test on Bikini Atoll in 1946. He is most likely to have died from primary prostate cancer that spread to his bones and brain. The most common cancer caused by nuclear radiation is cancer of the bone marrow, but he was unlikely to have suffered from primary bone cancer because it virtually never spreads to the prostate or pancreas. Brain cancer also does not typically spread to the prostate or the pancreas, and pancreatic cancer rarely metastasizes to the brain. 
Prostate cancer was most likely to have been his primary cancer because when it metastasizes, it usually goes to the bones and brain. The exposure to radiation would help to explain his death from prostate cancer at such a very young age. His lifestyle probably also contributed since drinking alcohol, overeating, lacking exercise and being overweight are all associated with increased risk for prostate cancer. We will never be certain of the cause, but the world lost perhaps its greatest mathematician when he was only 53 years old.
December 28, 1903 – February 8, 1957