President Obama paid tribute to former Pennsylvania Sen. Arlen Specter, who passed away Sunday at age 82 from complications related to non-Hodgkin lymphoma.

“Arlen Specter was always a fighter,” Obama said in a statement released by the White House on Sunday.  “From his days stamping out corruption as a prosecutor in Philadelphia to his three decades of service in the Senate, Arlen was fiercely independent – never putting party or ideology ahead of the people he was chosen to serve.

“He brought that same toughness and determination to his personal struggles, using his own story to inspire others,” Obama continued. “When he announced that his cancer had returned in 2005, Arlen said, ‘I have beaten a brain tumor, bypass heart surgery and many tough political opponents and I'm going to beat this, too.’

"Arlen fought that battle for seven more years with the same resolve he used to fight for stem-cell research funding, veterans health, and countless other issues that will continue to change lives for years to come," added Obama. "Michelle and I send our thoughts and prayers to Joan and the rest of the Specter family.”

Obama and Specter served briefly together in the Senate before he was elected president, when Specter was a long-time Republican senator from Pennsylvania and Obama was a freshman Democratic senator from Illinois.

Their paths crossed again in 2009 when Specter switched parties to become a Democrat after his vote in favor of Obama’s economic stimulus package drove conservatives to oppose his bid for a sixth-term in 2010.

Vice President Biden who served with Specter for many years in the Senate called his former colleague was “my friend and I admired him a great deal.” 

“For over three decades, I watched his political courage accomplish great feats and was awed by his physical courage to never give up,” said Biden in a statement. “Arlen never walked away from his principles and was at his best when they were challenged.”

Specter ran for the Democratic party’s Pennsylvania Senate nomination in 2010, and Obama supported him over long-time Democrat former-Rep. Joe Sestak. Despite Obama’s endorsement, however, Specter was defeated by Sestak, who went on to lose the general election to now-Sen. Pat Toomey (R-Pa.).

In a memoir earlier this year, Specter expressed frustration with his treatment by the president after switch parties, suggesting that Obama and Vice President Biden could have done more to help him in his campaign against Sestak. Specter said that Obama had rejected a request to campaign with him in the last few days of the race.

The centrist Specter's 30-year career in the Senate made him Pennsylvania's longest serving senator. 

This story was updated at 7:03 p.m.