"Jenn died at home in Oregon at 11:19 p.m. on Jan. 19. She had been battling breast cancer for the last five plus years," Survivor: Vanautu and Survivor: Micronesia Fans vs. Favorite cast member Eliza Orlins told TVGuide.com. "She had beaten it into remission once, but then it came back and was in her bones."
Lyon, who finished in fourth place during the tenth season of the CBS reality show in 2005, was diagnosed with stage-three breast cancer two months after the show wrapped.
"In the summer of 2004, I felt something in my right breast that didn't feel normal," Lyon told People in Oct. 2005. "I thought it was probably scar tissue related to my breast implants. So I let it go—for a long time."
Lyon said she opted to get a modified, radical bilateral mastectomy that summer, removing both breasts and 29 lymph nodes.
"The whole time she maintained a positive attitude. She was truly an amazing girl and I was lucky to know her," Orlins said. "Even just last week when I saw her at the 10-year reunion, we were all laughing and she had her same glowing smile on her face."
Orlins also said that despite Lyon's condition, she was still actively involved in the fight against breast cancer and hosted several fundraising events. She recently opened a Christmas tree lot in Los Angeles that promised 10 percent of its proceeds would go to breast cancer research.
"She was an inspiration," said Orlins. "Jenn brought more good to this world in her almost 38 years than most will in a lifetime."