tyler hamilton and frankie andrei ewe have both admitted using drugs. yet armstrong vigorously says he is clean. >> we have nothing to hide. we have nothing to run from. >> reporter: in television ads -- >> what am i on? i'm on my bike, busting my ass six hours a day. >> reporter: his image, his comeback, his cancer foundation, is the stuff of movies. off the bike, armstrong is a pitchman for everything from cars to beer. but most importantly, to thousands of cancer patients, lance armstrong lives. his trademark livestrong is literally a word to live by for cancer survivor s the world ove. he gives so much hope to so many people, they travel thousands of miles just to see him. just to see the man who beat cancer, got back on his bike and beat the toughest race on earth. >> i've seen him progress and go through cancer, win the tour de france seven times. many people will say he's the most phenomenal comeback in cycling history. >> reporter: during the time he was fighting cancer, before he'd won a tour de france, his teammate and friend frankie andrei ew