“Mary Kate’s eye is drooping a little. Do you see that?”

At just 2 years old, little Mary Kate touched more hearts than most do in a lifetime. What began with a slightly drooping eye soon led to heartbreaking news—a diagnosis of ATRT, a rare and aggressive brain and spinal tumor.

Mary Kate Funk was born three weeks early on November 26, 2018, in California, the joyful fourth child of Allison and her husband. She arrived healthy and quickly became known for her warm, radiant smile that filled every room. Her three older siblings adored her, and she was described as calm, tiny, and impossibly lovable.

On January 18, 2020, while at her brother’s basketball game, a family member noticed the slight droop in Mary Kate’s left eye. What first seemed minor led to emergency evaluations, ophthalmology visits, and an eventual MRI. Initial hopes of a benign growth were dashed when follow-up imaging revealed rapid tumor growth and widespread involvement of her spine. A biopsy confirmed atypical teratoid rhabdoid tumor (ATRT)—an aggressive embryonal cancer of the central nervous system that primarily affects very young children, often under age 3.

ATRT is rare and fast-growing. Mary Kate’s case involved both the brain and spine. She faced the diagnosis with remarkable courage. Over the following months she endured three brain surgeries, 86 chemotherapy infusions, three rounds of high-dose chemotherapy with stem cell transplants at UCSF, 107 nights in the hospital, 25 sedations, and 50 blood and platelet transfusions. She completed treatment in Roseville, California, under dedicated local oncologists and the specialized team at UCSF, where her care drew on protocols shaped by leading experts in the field. Through it all, she kept eating, rarely complained, and continued to flash her bright smile. “You would never know she was sick with such an aggressive type of cancer,” her mother later wrote.

After intensive therapy, residual and new disease appeared. Additional outpatient treatments, including intrathecal chemotherapy via an Ommaya reservoir, followed. In November 2020, further progression and a prolonged seizure led to a final hospital admission. On November 22, 2020—just four days before her second birthday—Mary Kate passed away peacefully, surrounded by love.

Her family has channeled their grief into lasting good. They established the Mary Kate Funk Foundation to provide financial support for other families navigating childhood cancer. A small business, MK’s Tiny Toys, was also created in her memory, with proceeds benefiting the foundation. Her parents emphasize that Mary Kate continues to guide them, bringing hope and love to others.

Mary Kate’s short life remains a powerful reminder of the resilience of children facing rare and aggressive cancers, the strength of families who walk beside them, and the urgent need for continued research and support for pediatric brain tumors such as ATRT.

Sources

• Love What Matters personal essay by Allison Funk (March 2021, updated later), detailing Mary Kate’s diagnosis, treatment, and passing.
• Medical context on ATRT drawn from established clinical descriptions (rare, aggressive CNS embryonal tumor primarily affecting infants and toddlers).