Beau Biden, son of US Vice President Joe Biden, has died after battling brain cancer, the vice president said on Saturday."The entire Biden family is saddened beyond words. We know that Beau's spirit will live on in all of us, especially through his brave wife, Hallie, and two remarkable children, Natalie and Hunter," said a statement released by the White House.Biden was 46 and a former Delaware attorney general. He had been hospitalized this month for treatment at the Walter Reed Army Medical Center outside Washington.After eight years as attorney general, Beau Biden joined the investor law firm Grant & Eisenhofer in 2015.He served a yearlong tour in Iraq as a captain in the Delaware Army National Guard and underwent surgery at a cancer center in Texas last year. He suffered a mild stroke in 2010.President Barack Obama paid warm tribute to Beau Biden, saying he took after his father."He studied the law, like his dad, even choosing the same law school. He chased a life of public service, like his dad, serving in Iraq and as Delaware's Attorney General," Obama said in a statement."Like his dad, Beau was a good, big-hearted, devoutly Catholic and deeply faithful man, who made a difference in the lives of all he touched, and he lives on in their hearts."The vice president has faced family tragedy before. Shortly after winning election to the US Senate in 1972, his wife Neilia and three children were in a car crash. Neilia and their daughter were killed, while their two sons, Beau and Hunter, were injured.Joe Biden has been Obama's vice president since the president first took office in January 2009.