Mike Lunsford, an executive vice president who leads the voice and access business unit at EarthLink, will act as the interim CEO and immediately assume Betty's daily responsibilities.
Previously, Lunsford managed 70 percent of EarthLink's revenue and 1,200 employees. He started at EarthLink in 1999 and is credited with overseeing the introduction of the company's broadband service, according to an EarthLink statement.
Betty has been leadingcontracts.
"and has the determination to beat this disease. Our thoughts and prayers are with him, his wife and his family," Sky Dayton, EarthLink's founder and the current , said in a statement.
Robert Kavner, chairman of EarthLink's board of directors, also released a statement expressing his confidence in Lunsford's leadership while Betty is on leave.