OMAHA, Neb. -- Billionaire investor Warren Buffett and his wife Susan have donated $6 million to five California medical specialists who coordinated Susan Buffett's recent mouth cancer treatment.

A University of California-San Francisco professor found a growth in the base of Susan Buffett's mouth last October. That led to tumor-removal surgery at the university's medical center near Susan Buffett's San Francisco home.

The medical team credited a treatment team and Susan Buffett's own courage and fortitude for her recovery.

The donated funds will be for each of the doctors to use at their own discretion for research.