JAK2 and acute lymphoblastic leukemia: We restricted the further analysis only to DS-ALL primary presentation samples, and quantitatively compared those that PCA grouped into Cluster 1 (PCA-predicted standard-risk (SR)) to those in Cluster 2 (PCA-predicted high-risk (HR)), for the basal activities (Fig. 5d top row) and TSLP-induced activities (Fig. 5d bottom row) of pan-RAS, JAK2, STAT5, MEK1/2, ERK1/2 and rpS6.