SEATTLE -- Microsoft co-founder Paul Allen has been diagnosed with non-Hodgkin's Lymphoma, Vulcan Inc. has confirmed.

"It's a tough day for everybody here and I think anybody who cares about Paul, which in this town is a lot of people," said David Postman, spokesman for Vulcan Ventures.

He said the diagnosis will not impact Allen's day-to-day work with the company.

"He remains as chairman, he remains active, he's working," Postman said. "He has just as much a presence as always."

TechFlash.com first reported Allen's sister, Jody Allen, notified Vulcan employees of her brother's health condition on Monday via an internal e-mail.

Allen left Microsoft in 1983 after being treated for Hodgkin's disease, a type of cancer that attacks the body's system for fighting off infection.

He was said to have remained cancer-free since thanks to early detection, but last year, Allen pulled out of a banquet held in his honor due to undisclosed health concerns, TechFlash.com said.

Allen gave the Fred Hutchinson center $2 million in 2003 to help launch an early detection and intervention initiative, and $2 million in 1996 to build a new home for its clinical research division.

The Paul G. Allen Foundation was launched in 2004 through the consolidation of Allen's six private foundations. Together with its predecessor foundations, it has awarded more than $300 million in grants since 1997 to organizations serving people in Washington, Oregon, Idaho, Alaska and Montana.