Gary Sinise is honoring his late son, McCanna Anthony “Mac” Sinise, who died Jan. 5 from a rare form of cancer called chordoma. He was 33.

The actor, famous for his roles in Forrest Gump, Apollo 13, The Green Mile and CSI: NY, posted a photo of his son on Instagram Tuesday, with text that read, “In Honor & Memory of McCanna ‘Mac’ Sinise 1990-2024.”

In the caption, the Of Mice and Men star directed his followers to the Gary Sinise Foundation website to read his heartfelt tribute to Mac.

“Like any family experiencing such a loss, we are heartbroken and have been managing as best we can,” he wrote in the tribute. “As parents, it is so difficult losing a child. My heart goes out to all who have suffered a similar loss, and to anyone who has lost a loved one. We’ve all experienced it in some way. Over the years I have met so many families of our fallen heroes. It’s heartbreaking, and it’s just damn hard.”

The actor said his son was diagnosed in 2018, the same year his wife, Moira Harris, was diagnosed with stage 3 breast cancer; she is now cancer-free after months of treatment.

Chordoma is a slow-growing cancer of tissue found inside the spine, according to the National Cancer Institute, which states that one in 1 million people worldwide are diagnosed with the disease each year.

In addition to Mac, Gary Sinise is also a father to two other children, daughters Sophie and Ella.

Copyright © 2024, ABC Audio. All rights reserved.