In paper from 2005, it was demonstrated that lenalidomide had a hematological activity in patients with low-risk MDS without response to erythropoietin therapy whereas patients with del(5q) have higher response rate (83 %) in comparison to subjects with normal karyotype (57 %) and other chromosomal aberrations (12 %) [13]. Here, EPO is linked to myelodysplastic syndrome.