Additionally, expression of other IRE1α/XBP1s-target genes, including XBP1s, HIF1α, DDIT4, and JMJD1A, was increased in ALDH+ cell–enriched tumor spheroids (Supplemental Figure 7F), suggesting that the UPR pathway was activated in spheroid cultures and in CSCs. This evidence concerns the gene HIF1A and neoplasm.