We found that ESR1 was most highly expressed in MS Clusters 0 and 2, whereas expression of ER target genes and enrichment of ER-associated gene signatures was observed in MS Clusters 1 and 2, suggesting that ER is active in MS Clusters 1 and 2 (Fig. 4B, C and Additional file 2: S. Table 8). This evidence concerns the gene ESR1 and myeloid sarcoma.