SGPP1 and Miyoshi myopathy: This expression pattern of GFI1-dependent elevated SphK1 mRNA (Figure S2A) and decreased SGPP1 mRNA (Figure S2B) was confirmed in other MM cell lines (H929 (p53 WT), KMS-11 (p53 null), and RPMI-8226 (p53 mut)) overexpressing GFI1 versus their controls.