SPHK1 and acute myeloid leukemia: To determine whether sphingolipid biosynthesis pathway gene expression is regulated by TSC2, we reanalyzed previously published genomic data from TSC2-null AML-derived cells — 621-102 (51) — and found that genes participating in the sphingolipid pathway were upregulated in TSC2-null cells (Figure 3A), including ASAH1, DEGS1, and SPHK1 transcripts, compared with TSC2-addback 621-103 cells (Figure 3B, Supplemental Figure 3, and Supplemental Tables 1 and 3; ASAH1P < 0.0001, DEGS1P < 0.0001, and SPHK1P = 0.0034 by unpaired t test).