Armstrong: "Difficult couple of weeks"

AUSTIN (KXAN) - At the 15 year anniversary celebration for the Livestrong Foundation, Lance Armstrong said he's been through a "difficult couple of weeks" and urged supporters of his cancer-fighting charity to stand behind its mission.

Armstrong, a cancer-survivor, founded the Livestrong Foundation in 1997. Friday evening kicked off a weekend of celebrations for the organization's anniversary celebration.

He stepped down as Livestrong chairman Wednesday in an effort to ward off damage caused by doping charges against him.

Armstrong gave the welcoming remarks to the crowd Friday. The event drew 1,700 supporters, cancer survivors and Armstrong friends, and they gave him a standing ovation before he spoke.

Actor Sean Penn told reporters on the yellow carpet about Armstrong, "A champion is a champion is a champion."

Some of the attendees were current cancer patients whose services the Livestrong charity has helped, like Laurey Masterson, who traveled to Austin from North Carolina.

"I have been helped by Livestrong at the YMCA to get me back on my feet," said Masterson. "Lance is my hero. He's lived through enormous adversity and continues to do so and he is my hero and will continue to be so."

Armstrong, who denies using performance enhancing drugs to win the Tour de France seven times, did not address doping evidence presented last week by the U.S. Anti-Doping Agency.

"Tonight is 15 years of inspiring people all over the world," said former Atlanta Falcon Chris Draft, who lost his wife to lung cancer last year. "So I don't think that the other things that are happening really change that because that's lives."

The Livestrong Foundation has raised more than 450 million dollars since 1997 and it has helped more than 2.5 million people fighting the disease in the United States.

Maria Shriver, Ben Stiller and Penn were on the guest lis Friday while  Robin Williams, Norah Jones and Stephen Marley entertained the crowd.

Even though Nike dropped Armstrong, the company and Livestrong will both take part in a special presentation at Saturday's UT-Baylor game. The second quarter will be dedicated as the Livestrong quarter and the entire student section will reveal LIVESTRONG t-shirts Nike created especially for the game.

On Sunday, almost 4,000 riders are expected to participate in the "Ride for the Roses" in downtown Austin.