"Instead today we pick out your gravesite," said CNN correspondent Rene Marsh, whose son Blake died of pediatric brain cancer on Thursday

Rene Marsh has a poignant birthday wish following the death of her 2-year-old son. 

Just two days after sharing the tragic news that her son Blake had died after a battle with pediatric brain cancer, the CNN correspondent shared a heartbreaking post about how she was spending her birthday this year.  

"I always expected you to help me blow out the candles. Instead today we pick out your gravesite," she wrote on Instagram alongside a photo that showed her celebrating her "very first birthday with Blake circa 2019," which was taken when her son was 1-month-old.

Marsh went on to share that in honor of her son, she wants to "do more for children like Blake."

"As cruel and unnatural as this feels, there are more children with brain cancer whose doctors have told their parents there's 'nothing more we can do' 'meanwhile other children are experiencing toxicity from chemo drugs used in children but designed for adults," she wrote. "My birthday wish today is to collectively do more." 

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

"My birthday wish is to wipe out pediatric cancer," she added in another Instagram Story as she encouraged her followers to donate to help make her wish a reality.

"Pediatric brain cancer is the deadliest form of pediatric cancer," she added. "Cancer is the #1 cause of death by disease in children after infancy, yet the U.S. only spends 4% of its annual cancer research budget on pediatric cancer."

Bringing the post to an end, she shared a link to where people can donate to the Pediatric Brain Tumor Foundation in honor of her son.  

rene marsh
Rene Marsh and son
| Credit: Rene Marsh/Instagram

As she mourned the death of her son this week, Marsh shared a touching message to her "dear sweet Blake," reflecting on all the lessons she learned from her child

"In your 25 months on earth you taught me how much strength I had stored up in reserve that I didn't know I had," she wrote. "You taught me endurance. You taught me a depth of love I have never experienced. You inspired me to keep going when I wanted to give up. You helped me prioritize what is truly important in this life."

"I am forever changed because of you, my son," Marsh added of her son, whom she welcomed with husband Kedric Payne in March 2019.

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.

Although Marsh wrote that she wished "we had more time together," she emphasized how "grateful" she was for every day with her son. "The good times we shared are forever in my heart," she wrote, noting that she is "dedicated to fighting pediatric cancer for the rest of my life."

"I will do it not just to spare other parents from this unbearable pain but I will do it to forever honor you, Blake. Your life was not in vain my sweet angel," she added. "Mommy loves you and I look forward to holding and kissing you when we meet again."

In February, Marsh revealed in an opinion piece on CNN's website that Blake's cancer had been in remission for six months before they were "blindsided" by its return in November 2020.

After sharing news of Blake's death on Thursday, Marsh also posted a statement on Twitter, thanking "all the doctors and nurses at #JohnsHopkins who cared for and loved Blake over the past year and a half."