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attends Hollywood Unites for the 5th Biennial Stand Up To Cancer (SU2C), A Program of The Entertainment Industry Foundation (EIF) at Walt Disney Concert Hall on September 9, 2016 in Los Angeles, California.

Beverly Hills, 90210 cast members are paying tribute to ailing co-star Shannen Doherty.

Doherty is being treated for breast cancer and didn’t take part in a 90210 reunion panel at the Rewind Convention in Chicago over the weekend.

Luke Perry, whose character had an on-screen romance with Doherty’s, told the audience on Saturday that Doherty was “a very big part of the success of the show.” He added that Doherty is “not doing well right now but sometimes her contributions are minimised.”

Fellow cast mate Jennie Garth praised Doherty on Instagram by sharing a picture that night with a quote, “Fight Like A Brenda”, a reference to Doherty’s 90210 character, Brenda Walsh. Garth calls Doherty the “strongest lady I’ve ever known.”