Pat Dollard | Young Americans

BOSTON — Sen. Ted Kennedy has been diagnosed with a malignant brain tumor, which doctors identified as the cause of his seizures over the weekend.

The 76-year-old Massachusetts Democrat was diagnosed with the tumor Tuesday morning after he underwent a biopsy, sources told FOX News.

“Preliminary results from a biopsy of the brain identified the cause of the seizure as a malignant glioma in the left parietal lobe,” his doctors said in a statement, adding that treatment would likely include “combinations of various forms of radiation and chemotherapy.”

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The senator has been hospitalized in Boston since Saturday, when he was airlifted from Cape Cod after a seizure at his home. He suffered another one en route to Massachusetts General Hospital, sources told FOX News.

His wife and children have been with him each day but have made no public statements.

His doctors said that he was in “good condition” and had not suffered any more seizures since Saturday.

Kennedy’s colleagues on Capitol Hill reacted with shock and sadness Tuesday morning, but expressed confidence in his ability to fight through the illness.

“Every one of us knows what a big heart this fella’ has. He’s helped millions and millions of people,” said fellow Massachusetts Sen. John Kerry, D. “Everybody needs to pull for him and his family and remember that this guy is an unbelievable fighter.”

“I’m betting on Senator Kennedy,” said Republican Pennsylvania Sen. Arlen Specter, who himself has battled cancer. “He’s been such a champion on so many causes … he’s been a shining example of crossing the aisle.”

But according to sources familiar with the situation, the prognosis for Kennedy is not optimistic and word is circulating through political circles in Massachusetts and on Capitol Hill that because the tumor is inoperable it can only be dealt with through chemotherapy and radiation.

Malignant gliomas are a type of brain cancer diagnosed in about 9,000 Americans a year — and the most common type among adults. It’s an initial diagnosis: How well patients fare depends on what specific tumor type is determined by further testing.

Average survival can range from less than a year for very advanced and aggressive types — such as glioblastomas — or to about five years for different types that are slower growing.

“The news has been met throughout the country with great concern,” said House Speaker Nancy Pelosi, D-Calif.

Dr. Lee Shwamm, vice chairman of the Department of Neurology at Massachusetts General, and Dr. Larry Ronan, Kennedy’s primary care physician, said in their statement that Kennedy will continue to undergo testing to determine the best course of treatment.

“Senator Kennedy will remain at Massachusetts General Hospital for the next couple of days according to routine protocol. He remains in good spirits and full of energy,” they said.

President Bush was notified by his staff of Kennedy’s diagnosis at 1:20 p.m.

“He said he was deeply saddened and would keep Senator Kennedy in his prayers,” spokeswoman Dana Perino said.

Kennedy, the second-longest serving member of the Senate and a dominant figure in national Democratic Party politics, was elected in 1962, filling out the term won by his brother, John F. Kennedy.

His eldest brother, Joseph, was killed in a World War II airplane crash. President Kennedy was assassinated in 1963 and his brother Robert was assassinated in 1968.

Kennedy is active for his age, maintaining an aggressive schedule on Capitol Hill and across Massachusetts. He has made several campaign appearances for Sen. Barack Obama in February, and most recently last month.

(Fox)