Patrick Dempsey's mother has passed away at the age of 79. She died on Monday, March 24, after a long battle with ovarian cancer.

Amanda Dempsey, the actor's mother, was the inspiration behind the Patrick Dempsey Center for Cancer Hope & Healing, a cancer support organization that the 'Grey's Anatomy' star and his sisters founded in 2008. The center is located at the Central Maine Medical Center in Lewiston, Maine, where his mother had long been treated.

Peter Chalke, the president and CEO of Central Maine Healthcare, honored Amanda in a statement released yesterday, March 25.

"The entire Central Maine Medical family mourns the passing of Amanda Dempsey. [She] was both a great lady and a determined fighter who displayed tremendous courage, class and grace during her long battle with cancer," Chalke stated. "We will miss Amanda deeply, but we were all blessed by knowing her and being inspired by her life story."

For the past five years, Amanda -- along with her son, daughters and three grandchildren -- led a cancer survivor walk called the Dempsey Challenge. The Dempsey Challenge has helped raise over $5 million to support the Dempsey Center for Hope & Healing.

"It was not uncommon for Amanda to be behind the scenes volunteering at the Center, sewing handmade comfort items to be given to cancer patients, keeping an eye on the quality control of the items or tidying up the storage closet," reads a press release about Amanda on the Dempsey Center's website. "She often brought in apples she picked from her own apple trees, or homemade jam, and even sewed individualized door hangings for staff members’ offices when the Center moved to its new location in 2012. In a way, Amanda was like a mother to all who walked through the doors of the Dempsey Center, whether they even knew it or not."

Our thoughts are with Patrick Dempsey and his family during this difficult time.