WASHINGTON — For millions of Americans, the announcement that Sen. Edward M. Kennedy has brain cancer was at least the fourth chapter of a tragic epic that began on Nov. 22, 1963, with the assassination of John F. Kennedy.

It continued through the death of his brother Robert in 1968, then of John Jr. in a plane crash in 1999.

And yesterday it was the sudden reminder of the mortality of the last surviving son of Joseph P. Kennedy, the patriarch who created this family of strivers and doers.

"I'm having a hard time remembering a day in my 34 years here I've felt this sadly," said Patrick Leahy, the Vermont Democrat who has been Kennedy's colleague for most of his 45 years in the Senate.

Sen. John Warner, R-Va., a colleague since 1979, said: "I am so deeply saddened, I have lost the words." Friends and colleagues poured forth encouraging and admiring tributes.

Doctors discovered the tumor after the 76-year-old senator suffered a seizure over the weekend.

Dr. Lee Schwamm, vice chairman of neurology at Massachusetts General, and Dr. Larry Ronan, Kennedy's primary physician, said the senator "has had no further seizures, remains in good overall condition, and is up and walking around the hospital."

"He remains in good spirits and full of energy," the physicians said.

An Associated Press photographer who was given access to the senator yesterday captured Kennedy, dressed in a gray sweater and dark slacks, joking and laughing with family members as he sat at a table in a family room at the hospital. Kennedy's wife since 1992, Vicki, and his five children and stepchildren have been at his bedside.

Malignant gliomas are diagnosed in about 9,000 Americans a year. In general, half of all patients die within a year.

Kennedy's doctors at Massachusetts General Hospital said he had a malignant glioma in the left parietal lobe, a region of the brain that helps govern sensation, movement and language.

Seizures can be caused by a wide variety of things, some of them relatively minor. The finding of a brain tumor — and specifically a glioma, an especially lethal type — was about the worst possible news.

Kennedy's doctors said he will remain in the hospital for the next couple of days as they consider chemotherapy and radiation. They did not mention surgery, a possible indication the tumor is inoperable.

Outside experts gave him no more than three years — and perhaps far less.

"As a general rule, at 76, without the ability to do a surgical resection, as kind of a ballpark figure you're probably looking at a survival of less than a year," said Dr. Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles.

PROMINENT FAMILY

There has never been another American family quite like the Kennedys, who have combined accomplishment, glamour, melodrama, tragedy and mythology in ways almost magical, creating an intense public fascination that has lasted for half a century.

John F. Kennedy and wife Jacqueline Bouvier Kennedy began the story by creating an American royal court — "Camelot," the writer Theodore White called it. Their creation lasted only a thousand days, but this was long enough to hustle Edward Moore Kennedy into the Senate in 1962, when he was just 30 years old.

It was the sort of maneuver that infuriated Kennedy-haters — and since the 1930s, when Joe Kennedy, one of the country's richest men, did not hide his sympathy for Nazi Germany, there had always been Kennedy haters.

In 1960, when he won the presidency, John Kennedy resigned from the Senate and prevailed on the lame-duck Democratic governor of Massachusetts to appoint Kennedy's former roommate Benjamin Smith, to the seat. Smith would keep it warm until 1962, when Edward Kennedy, known to all as Teddy, would reach the constitutionally mandated age of 30 and could run for the Senate.

Kennedy pushed aside Edward McCormack, son of House Speaker John McCormack, D-Mass., and himself attorney general of Massachusetts, who coveted the Senate seat. McCormack famously quipped that if Edward Moore Kennedy had been Edward Moore, no one would have considered him a serious candidate for Senate.

John Seigenthaler, who worked with Robert Kennedy in the Justice Department when he was attorney general, recalled yesterday a conversation between Bobby and Teddy on the subject of the McCormack family's complaints. "Ignore those people. We've got to pursue what we've got to pursue" was the way Seigenthaler remembered it.

Teddy Kennedy defeated McCormack for the Democratic nomination and sailed into the Senate, where he has served longer than anyone but the perpetual Robert Byrd of West Virginia. And Byrd wept as he prayed for "my dear, dear friend, dear friend, Ted Kennedy" during a speech on the Senate floor yesterday.

"Keep Ted here for us and for America," said the 90-year-old Byrd, who is in a wheelchair. He added: "Ted, Ted, Ted. My dear friend. I love you and miss you."

EARNING RESPECT

At first, Senate colleagues presumed that the new junior senator from Massachusetts was a lightweight, but before long he had become a serious legislator.

Rep. Barney Frank, D-Mass., yesterday recalled his first major legislative accomplishment, the Immigration and Nationality Act of 1965, which ended preferences that favored white immigrants from Europe over all others. Kennedy discovered that he was good at legislating, and that he liked it.

Frank said Kennedy has been "the most influential senator in American history," a debatable proposition, but not a dismissible one.

"JFK brought charm and wit to government," said Ronald Steel, a historian and author of a book on Robert Kennedy, "and Bobby is remembered for what might have been, but Ted should be thought of as someone who showed how government could be made to serve the people."

His two brothers made the family's reputation, but it was Ted Kennedy, blessed with a decades-longer life, who worked with the nuts and bolts of government and politics to make things happen.

"On numerous occasions," added Sen. John McCain of Arizona, now the presumptive Republican nominee for president, "I have described Ted Kennedy as the last lion in the Senate ... because he remains the single most effective member ... if you want to get results."

NAME LIVES ON

Last of the lions, perhaps, but not last of the Kennedys. Rep. Patrick Kennedy, D-R.I., called political allies yesterday to report on his father's condition and to assure them he will battle this illness with all the forces at his command. Numerous offspring of the John-Robert-Edward generation have gone into public life or public service.

"The family culture has survived," Seigenthaler said. But no member of the younger generation has shown signs of the big ambitions that motivated the three brothers who have left such big footprints.

Theodore Sorensen, JFK's speechwriter and alter ego, observed yesterday: "Only the Adams family in the earliest days of the republic had the kind of stature, respect and impact on public life as the Kennedys."

The Associated Press contributed to this report.