PIWIL2 and myelodysplastic syndrome with single lineage dysplasia: Beck et al. [17] reported piRNA enrichment in unsorted BM cells from patients with refractory anemia (RA), a lower-risk MDS (LR-MDS) subtype, and reported that PIWIL1 and PIWIL2 expression was significantly upregulated in RA patients compared with controls and HR-MDS patients.