Sarah Michelle Gellar posts about Shannen Doherty 

Shannen Doherty reveals cancer may have spread

Shannen Doherty shares breast cancer update after shaving head

On Monday, Sarah Michelle Gellar shared an emotional Instagram post dedicated to her friend, Shannen Doherty, who is currently battling breast cancer.

alum, and wrote, “My #mondaymuse (and really every day #muse) is my brave friend @theshando, I’ve always said she is one of the most loyal friends I’ve ever known, and now while she is facing the toughest journey of her life, she is sharing it with friends she has never met in the hopes of helping other people who are going through the same struggle. That’s a true friend #F—Cancer.” 

My #mondaymuse (and really every day #muse) is my brave friend @theshando. I’ve always said she is one of the most loyal friends I’ve ever known, and now while she is facing the toughest journey of her life, she is sharing it with friends she has never met in the hopes of helping other people who are going through the same struggle. That’s a true friend #FuckCancer

Doherty was originally diagnosed in March 2015, and last week in an emotional sitdown interview with

, she revealed that her cancer has spread. “The unknown is always the scariest part,” she said. “Is the chemo going to work? Is the radiation going to work? You know, am I going to have to go through this again, or am I going to get secondary cancer?”

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