Fans are becoming concerned about whether "Good Morning America" co-host Robin Roberts will be able to continuing her anchoring career after news that she has been diagnosed with myelodysplastic syndrome (MDS), or preleukemia.

Although unsure about how her body will react to the disease, Roberts is confident that she will soon be on the track to recovery.

"My doctors tell me I'm going to beat this-and I know it's true," wrote Roberts to her colleagues in a letter, which was then posted on the ABC blog.

Roberts announced on Monday that she will be going through chemotherapy as a part of her pre-treatment. She later reassured fans that she would start it today. She also warned them that she may be wearing a bandage tomorrow, but to not be startled by it.

According to the National Cancer Institute, Preleukemia is a disease that occurs when healthy blood cells cannot be produced in a person's bone marrow. Symptoms include shortness of breath, pale skin, feeling tired, fever, and easy bleeding or bruising.

Roberts said on Monday's show that she is planning on receiving a bone marrow transplant by the end of the summer or early fall from her sister. Roberts has become a big supporter of bone marrow donation and encourages people to be donors.

"Bone marrow donors are scarce and particularly for African-American women," said Roberts. "I am very fortunate to have a sister who is an excellent match, and this greatly improves chances for a cure."

Roberts, who first learned that she had the disease in April, said she had been aware of her diagnosis for a while now and that she will not let it stop her from anchoring "Good Morning America".