In patients with complete cytogenetic response, Tehranchi et al. demonstrated that the 5q deletion remained detectable in patients with MDS-del(5q), using FISH of sorted CD34+, CD38−/low, and CD90+ HSCs at the time of complete response during lenalidomide treatment [93], further indicating that complete cytogenetic response does not necessarily reflect and capture the quiescent malignant stem cell population. This evidence concerns the gene CD34 and myelodysplastic syndrome.