If I'm not mistaken, the "news" about downsizing in the Oncology BU started circulating about a month ago. Within a week, at least ten people quit on their own, saving the company quite a bit in severance.
This is not unique to Oncology, it has happened many times before when rumors start going around about layoffs - and there have been cases when they didn't even turn out to be true in the end.
This makes me think this is an orchestrated effort by the company - avoid major costs by scaring people into quitting. I could just be paranoid, but it sure seems like it to me...