Earlier this month, Microsoft (MSFT) co-founder Paul Allen was diagnosed with diffuse large B-cell lymphoma, a form of non-Hodgkins lymphoma. According to a memo sent to Allen's staff by his sister Jody, he has begun chemotherapy and is optimistic about his chances of beating the disease.

This is not Allen's first experience with cancer: 26 years ago, he was diagnosed with Hodgkins Lymphoma. At the time, he was chief technical officer for Microsoft, which he founded in 1975 with high school friend Bill Gates. He left the software company to fight the disease, but ultimately decided not to return. While his $11.5 billion fortune, generated by his early investment in Microsoft, pales beside that of Gates, it has still been sufficient to land him the number 17 spot on the Forbes 400 list of wealthiest Americans.
Since his bout with Hodgkin's disease, Allen has used his wealth to pursue his interests in sports, music and space travel. In 1988, he bought the Portland Trailblazers NBA team and, nine years later, he added the Seattle Seahawks football team to his holdings. Today he also has a part ownership in the Seattle Sounders soccer team.

In terms of music, he has continued to play with his own band while amassing a huge collection of rock and roll memorabilia. This became the basis of his Experience Music Project, an interactive, Frank Gehry-designed museum in Seattle. Later joined by the Science Fiction Museum and Hall of Fame, the two museums demonstrate Allen's involvement in "venture philanthropy," a hands-on, results-oriented approach to charitable giving. He has also funded the Flying Heritage Collection, a museum that showcases his personal collection of vintage aircraft.

Lest his eyes seem too focused on the past, Allen also bankrolled SpaceShipOne. In 2004, the aircraft won the Ansari X prize, a contest to create a reusable, non-government-funded spacecraft. He is also funding the Allen Telescope Array, a collection of radio telescopes that are designed to observe space and search for extraterrestrial life.

Survival rates for Allen's disease, diffuse large B-cell lymphoma, vary widely based upon subtype and other factors. More aggressive versions have five-year remission rates as low as 30%, while less aggressive types can have survival rates as high as 90%. Unlike his previous bout with cancer, Allen has decided to remain at work in his capacity as chairman of Vulcan, Inc., a private asset management company.