Paul Allen, co-founder of Microsoft, has been diagnosed with non-Hodgkin’s lymphoma, his sister has said.
Jody Allen, the chief executive of Mr Allen’s investment firm Vulcan Inc, told staff in a memo that her brother had begun chemotherapy.
Mr Allen, 56, founded Microsoft in 1975 with Bill Gates but left in 1983, when he was diagnosed with another form of cancer – Hodgkin’s disease.
He survived that bout after receiving successful treatment.
“He received the diagnosis early this month and has begun chemotherapy,” Jody Allen wrote to staff.
“Doctors say he has diffuse large B-cell lymphoma, a relatively common form of lymphoma.
“Paul is feeling OK and remains upbeat. He continues to work and he has no plans to change his role at Vulcan.”
She added that he was “optimistic he can beat this”.