This is a prospective trial of Revlimid for subjects who have a blood cell cancer called myelodysplastic syndrome (MDS). Cells in their marrow make proteins through messages that are carried from the genes. The amount of the message tells researchers if the protein it is going to make is high or low. This is known as expression of genes. The purpose of this study is to conduct a prospective trial testing the idea that expression of specific genes can help to predict which patients will respond to study drug administration with Revlimid (lenalidomide).