Lance Armstrong

The Livestrong Foundation said it's "disappointed" with Lance Armstrong after he admitted to doping during his cycling career.

"We at the Livestrong Foundation are disappointed by the news that Lance Armstrong misled people during and after his cycling career, including us," reads a statement on the foundation's website. "Earlier this week, Lance apologized to our staff and we accepted his apology in order to move on and chart a strong, independent course. We look forward to devoting our full energy to our mission of helping people not only fight and survive cancer, but also thrive in life after cancer."

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On Thursday, Part 1 of Armstrong's confessional with Oprah Winfrey aired, in which he admitted that he used banned substances, including performance-enhancing substances like testosterone and blood-doping. He added that his years-long use of the substances was partly due to the entire cycling culture and that at the time, he didn't feel that using the substances was wrong or bad.

Armstrong, 41, who was diagnosed with testicular cancer in 1996, founded Livestrong in 1997 to support other people with the disease. In October, shortly after he was stripped of his seven Tour de France titles, Armstrong announced that he would be stepping down as chairman. Despite his admission, the foundation still thanks him for everything he's done for the cancer community.

"Even in the wake of our disappointment, we also express our gratitude to Lance as a survivor for the drive, devotion and spirit he brought to serving cancer patients and the entire cancer community. Lance is no longer on the Foundation's board, but he is our founder and we will always be grateful to him for creating and helping to build a Foundation that has served millions struggling with cancer."

Part 2 of Armstrong's interview with Winfrey airs Friday at 9/8c on OWN.