LEWISTON, Maine (AP) — The sixth Dempsey Challenge is a tough one for Patrick Dempsey and his sisters. It's the first time the cancer support fundraiser has been held since the loss of his mother, who inspired the bicycling and running event in Maine's second-largest city. The "Grey's Anatomy" star launched the Dempsey Challenge because of his mother's battles with ovarian cancer. Money raised from this weekend's event goes to The Patrick Dempsey Center for Cancer Hope & Healing, which he and his two sisters created in 2008 in partnership with the Central Maine Medical Center in Lewiston. Their mother, Amanda Dempsey, passed away in March. Patrick Dempsey was born in Lewiston and raised nearby.Read more on NewsOK.com