Microsoft co-founder Paul Allen diagnosed with cancer

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.