Mackenzie McKee's Instagram

Angie Douthit, the mother of Teen Mom star Mackenzie McKee, has died after a battle with brain cancer. She was 50.

"Momma @angiedouthit has crossed the finish line," Mackenzie wrote along with the Instagram image above. "She did not lose the battle, she [won]. She is healed and running in heaven in eternity. Idk anyone who left earth with such an impact, Your entire life you never [wasted] a chance to let the world know Gods love. When we would try to brag on what an amazing person you are you would respond with “it’s not me, it’s God.”

She continued: "Could you imagine this world if we all lived like Angie Douthit. She always said 'it’s easy, we were put on earth to share Gods love.” And boy did she. 700 daily post for you guys to read daily, hundreds of speaking engagements even when she could barely walk or speak, she simply trusted That God would speak through her. Momma, i did not deserve you. But you loved me so unconditionally. You were the glue that held me together. The one who always believed in me. Idk what I will do without you but I hope this goes by fast so I can hurry and come be with you. You passed a torch down to us and I will not fail you. I will live for Christ and love like him like you always taught me. I will make you proud, momma."

The Teen Mom Twitter account issued the following statement:

And shortly after Angie's passing, a touching tribute was featured on her Instagram account.

"On Monday, December 9 at 11:37pm, Angie finished her race," the caption reads. "Her last days were spent lovingly surrounded by family and friends as they prayed, sang, and shared funny Angie stories."

Angie's brave fight was featured on the most recent season of Teen Mom OG -- including the heartbreaking moment, below, when Angie updated her daughters about her devastating prognosis.

Our thoughts are with Mackenzie and her loved ones during this difficult time. Please leave your heartfelt messages in the comments.