Good Morning America anchor Robin Roberts said Monday morning that she has been diagnosed with MDS, a form of leukemia that affects the blood cells. Roberts, who won a fight against breast cancer five years ago, said that she will be undergoing a bone-marrow transplant. “Bottom line: I am going to beat this,” Roberts said Monday. “My doctors say it, and my faith says it to me.” The host’s older sister is a match for the transplant, and Roberts said she will likely undergo the procedure in the summer or fall. “It’s about focusing on the fight, not the fright,” Roberts said.