'Beverly Hills, 90210' Cast Pays Tribute to Shannen Doherty at Reunion

— -- Shannen Doherty may have been absent from a reunion of her "Beverly Hills, 90210" co-stars this weekend, but she was not forgotten.

Luke Perry and other castmates paid tribute to Doherty, 45, who couldn't make the reunion at RewindCon in Bloomingdale, Illinois, Saturday because she was undergoing treatment for breast cancer.

"None of us are up here today without Shannen," said Perry, 50, who played Dylan, the boyfriend of Doherty's character Brenda. "She’s been through a lot. She’s not doing well right now but sometimes her contributions are minimized. She’s been thrown under the bus. I’ve been accused of driving it. But she’s a very big part of the success of this show. She taught me a lot. I’m glad she was my scene partner. She was great at what she did in the character with me."

Perry appeared at Saturday's event alongside Tori Spelling, Jennie Garth, Jason Priestley, Gabrielle Carteris, Christine Elise and Vincent Young.

Later Garth posted a picture on Instagram that said "Fight Like a Brenda." Alongside it, she wrote, "To my soul sister @theshando strongest lady i've ever known. then and now. i used to be threatened by your spirit, now i'm in awe of it. you've taught me a lot about speaking my mind and not being afraid of my power. i'm so grateful that young me got to be friends with you. but especially "old" me! the best is yet to come on this crazy journey!! love you!"

Doherty revealed last year that she was diagnosed with breast cancer when she sued her former business managers for allowing her health insurance to lapse. That case reportedly was settled this past August.

The "Charmed" star underwent a mastectomy, and after learning that the disease may have spread beyond her lymph nodes, she began chemotherapy treatment. She has been documenting her battle on social media.

The Associated Press contributed to this report.