Former President, Jimmy Carter, announced that he has advanced cancer. But it is still not clear what kind of cancer he has. According to NBC, Carter, who was 90 years old, had a mass removed from his liver on Aug. 3.

"Recent liver surgery revealed that I have cancer that now is in other parts of my body. I will be rearranging my schedule as necessary so I can undergo treatment by physicians at Emory Healthcare. A more complete public statement will be made when facts are known, possibly next week," Carter said in a statement.

In May, Carter left Guyana stating that he was not well, according to NBC News.

The 39th president of the United States, was active despite his age and worked with groups such as Habitat for Humanity, winning the Nobel Peace Prize in 2002 and founding the nonprofit Carter Center in his home state of Georgia, according to NBC News.

It is reported that he had a family history of deaths due to cancer.

In 2007, Carter told The New York Times that he had CT scans twice a year and later MRI (magnetic resonance imaging) to look for tumors in his pancreas.

"This is a 90-year-old gentleman with apparent widespread disease. The goals of treatment would be his comfort. If chemo is considered it would need to take into account his age," Dr. Robert Mayer, a gastrointestinal cancer specialist at the Dana Farber Cancer Institute told NBC News. Mayer says a 90-year-old patient cannot tolerate the same treatment that could buy years of life for cancer patients in their 60s or 70s.

"Our thoughts and prayers are with Rosalynn and the entire Carter family as they face this challenge with the same grace and determination that they have shown so many times before," said President Obama in a statement. "Jimmy, you're as resilient as they come, and along with the rest of America, we are rooting for you, " the President added.