Microsoft co-founder Paul Allen has been diagnosed as suffering from cancer again.

According to a memo sent on Monday to employees of Vulcan, his outfit, Allen, who is a survivor of Hodgkin's disease, has been diagnosed with non-Hodgkin's lymphoma.

Vulcan CEO Jody Allen, who is also Paul Allen's sister, said that Allen 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.

Allen beat Hodgkin's a little more than 25 years ago and he is optimistic he can beat this, too, she said. The memo said that Paul was feeling OK and remained upbeat. He will be continuing to work and has no plans to change his job.

Jody Allen someone optimistically asks staff not to discuss the matter outside of the office.