The symptoms of glioma, the rare brain cancer that affected actress Kelley Mack have been revealed following her death at the age of 33.
The Walking Dead actress Kelley Mack's death was confirmed on August 2, 2025, in her hometown of Cincinnati, Ohio, where she "passed away peacefully" surrounded by her family, as reported by Metro.
The news was shared via social media posts and through a statement on CaringBridge, where her family told fans: “It is with indelible sadness that we are announcing the passing of our dear Kelley. Such a bright, fervent light has transitioned to the beyond, where we all eventually must go.”
Born Kelley Klebenow, she had built a solid career with 35 acting credits and five producer credits, finding fame for her portrayal of Addy in Season 9 of The Walking Dead, and later appearing as Penelope Jacobs on Chicago Med and FOX’s 9-1-1.
Her death followed a battle with glioma, a rare form of cancer affecting the central nervous system, which she went public with last year.
According to the Mayo Clinic, gliomas are a growth of cells that starts in the brain or spinal cord, which look similar to healthy brain cells called glial cells, which surround nerve cells and help them function.
As a glioma grows it forms a mass of cells called a tumor, which can grow to press on brain or spinal cord tissue and cause symptoms, which vary depending on which parts of the brain or spinal cord are affected.
Mack had been diagnosed with diffuse midline glioma (DMG) is a rare type of cancerous brain tumor, which is most common in children aged between five and 10 years old, but can affect adults too.
The tumor is found in the middle section of the central nervous system, usually the thalamus, spinal cord or brainstem, and the cancer cells have spread beyond the tumor and into healthy brain tissue.
The symptoms can be mild to begin with before worsening over weeks or months as the tumor grows, and include drooping on one side of the face, weakness in the facial muscles or the arms and legs, particularly on one side, clumsiness, and problems with speech or swallowing.
Other symptoms include fatigue, headaches, nausea or vomiting, problems with balance or walking and concentration issues, as well as back pain or seizures.
Mack had previously revealed she'd first noticed "persistent lower back pain" in October 2024, which worsened to the point she had to be rushed to hospital the night before Thanksgiving.
There, and "abnormal mass" was found on her spinal cord following an MRI scan.
According to reports from CNN, Kelley had been sharing updates with her fans throughout her journey. In a post from March, she wrote: “Overall, this journey has not been easy, but things are getting better — improvements are tough to see when you’re in the thick of it. Thank you again and again for the support and prayers.”
Her family confirmed her peaceful passing, revealing she was surrounded by her mother Kristen and her aunt Karen in her final moments: “Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present.
"Kelley has already come to many of her loved ones in the form of various butterflies. She will be missed by so many to depths that words cannot express.”
They also shared an emotional message about her bravery, adding: “She would want you all to know how much she loves you.
"And as her sister, I want you all to know how brave that tough SOB was, especially when she decided to make the leap to be reunited with God. I’m so proud of her.”
Mack revealed in January that she'd begun the first of 24 rounds of proton therapy, which she finished in March before undergoing physical therapy.
She is survived by her mother and father, Kristen and Lindsay Klebenow, sister Kathryn, brother Parker, grandmother and grandfather Lois and Larry Klebenow and boyfriend, Logan Lanier.