The "Here Comes Honey Boo Boo" star was diagnosed with stage 4 adrenal carcinoma in January.
Shannon announced the news on Sunday, sharing a photo of the family all together on Instagram.
“With the breaking heart, we are announcing that [Anna] is no longer with us,” she began the post. “She passed away in my home last night peacefully at 11:12 PM. She gave one hell of a fight for 10 months.”
Shannon added that Cardwell passed away “with her family around her,” and promised to share more updates in the days to come. She ended the post by writing, “We love y’all and continued prayers and thoughts for our family doing this difficult time.”
Cardwell first appeared alongside her mother and half-sister, Alana "Honey Boo Boo" Thompson, on TLC's Toddlers and Tiaras, and then on the family's spin-off Here Comes Honey Boo Boo, which launched in 2012.
News broke in March of this year that Cardwell had been diagnosed with stage 4 adrenal carcinoma in her liver, kidney, and lung. Four months later, her mother confirmed the diagnosis to be terminal.
Cardwell and Shannon have had a publicly strained relationship over the years. Prior to the family spinoff show, Cardwell moved out of Shannon’s house in 2003 to live with her grandmother. When the show was canceled by TLC in 2014, amid reports that Shannon was romantically involved with former boyfriend and convicted sex offender, Mark McDaniel, Cardwell came forward to say that McDaniel had sexually assaulted her when she was 8 years old.
The family has since reconciled, including at Shannon’s February wedding to Justin Stroud where all four of her daughters — including Lauryn "Pumpkin" Efird and Jessica "Chubbs" Shannon — were present.
"This was the first time the family had all been together since 2014," Shannon told PEOPLE at the time. "So it was really special to get married in a place where my family and I have had so many memories!"
Cardwell’s death comes days after Shannon asked fans on Instagram to keep the family in their thoughts. "Y’all we r asking for prayers for our family as we are going through this process… We will update y’all whenever we can just know that all of your thoughts and your prayers are very much appreciated during this time," Shannon wrote in her post, along with the hashtag, #CancerSucks.
Cardwell is survived by her two daughters: Kaitlyn, 10, and Kylee, 7.
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