Paul Allen being treated for non-Hodgkin's lymphoma

Fighting for a football stadium for the Seahawks and trolleys for South Lake Union is nothing compared with Paul Allen's latest battle.

The Microsoft co-founder was diagnosed earlier this month with non-Hodgkin's lymphoma, a form of cancer similar to the one that led to his early retirement from the software company in 1983.

"This is tough news for Paul and the family," his sister, Jody Allen, said in an e-mail Monday, disclosing the illness to employees of Vulcan, Allen's holding company. "But for those who know Paul's story, you know he beat Hodgkin's (lymphoma) a little more than 25 years ago, and he is optimistic he can beat this."

The son of a University of Washington librarian became one of the richest people in the world after he and childhood pal Bill Gates started Microsoft in 1975.

In recent years Allen, 56, invested heavily in Seattle real estate, becoming arguably Seattle's most influential developer and a player in state and local politics.

His largest chunk of land is in South Lake Union, where a planned biotech hub morphed into a dense neighborhood of condominiums and technology offices, including the emerging new headquarters of Amazon.com.

Allen's holdings also include Experience Music Project at Seattle Center, the Seattle Seahawks, the Portland Trailblazers and an aviation museum at Paine Field in Everett.

The new round of lymphoma follows a bout with heart disease that sidelined Allen earlier this year and led to a heart-valve replacement. Details were largely secret until he confided in a sports columnist for The Oregonian who had seen Allen accompanied by a doctor to Blazers games.

"I'm fine, finally," Allen told John Canzano in September. "I'm much, much better. I hit a few bumps in the road."

Now he's hit another bump.

Jody Allen provided some details of the cancer to employees of Vulcan, Allen's holding company.

"He received the diagnosis early this month and has begun chemotherapy. Doctors say he has diffuse large B-cell lymphoma, a relatively common form of lymphoma," she said in the e-mail, which was disclosed by Allen's spokesman.

"Paul is feeling OK and remains upbeat," she said. "He continues to work and he has no plans to change his role at Vulcan. His health comes first, though, and we'll be sure that nothing intrudes on that."

Neither was available for interviews. Their spokesman, David Postman, said Allen is still active at Vulcan.

"He remains just as involved as always," he said.

Lymphoma is a cancer that starts in cells called lymphocytes in the body's immune system, according to the American Cancer Society.

Non-Hodgkin's "is a fast-growing lymphoma, but it often responds well to treatment with chemotherapy," the society's Web site says. "Overall, about 3 out of 4 people will have no signs of disease after initial treatment, and about half of all people with this lymphoma are cured with therapy."

Risk factors include a weakened immune system, which can result from drugs taken during a transplant procedure.

Allen has also been under considerable stress over the past year as his biggest investment, St. Louis-based Charter Communications, filed for bankruptcy protection in March with $21.7 billion in debt.

Brier Dudley: 206-515-5687 or bdudley@seattletimes.com