Myelodysplastic syndrome patient US Marine Sgt. Ken Reich is treated by hemotology oncologist Krishna Komanduri MD, director of the Adult Stem Cell Transplant Program at Sylvester Comprehensive Cancer Center at University of Miami Hospital. Reich, who had a bone marrow transplant in June 2011, is now undergoing twice weekly photopheresis blood treatments to stimulate his immune system. EILEEN SOLER / FOR THE MIAMI HERALD

DIANE SAWYER, ROBIN ROBERTS, SALLY-ANN ROBERTS Byline: Ida Mae Astute Caption: This image released by ABC shows host Robin Roberts, center, with her sister Sally-Ann Roberts, right and ABC News' Diane Sawyer on "Good Morning America" Monday, June 11, 2012, after Robin Roberts announced she has been diagnosed with myelodysplastic syndrome, a blood and bone marrow disease once known as preleukemia. She says she will undergo chemo and a bone marrow transplant this year as "pretreatment" for the disease, which she says she has known about for several weeks. She says her sister is a great match for her. While she says she'll miss a day here and there, she'll remain on the air. (AP Photo/ABC, Ida Mae Astute) PubHistory: Ida Mae Astute / ABC News