Table 1.

Molecular classification of hepatoblastoma

Study	Levels	Study type	Characterized by	Subtypes of HB (clusters)	Features	Number of HBs
Cairo et al26	RNA	Transcriptomic	16-Gene signature gene expression profiling	C1, C2	C1: enriched in hepatic perivenous program-related genes; β-catenin membranous and cytoplasmic accumulation. C2: enriched in cell-cycle and stem-cell-related genes; β-catenin nuclear accumulation.	85
Cairo et al27	miRNA	Transcriptomic/epigenetic variation	4-miR signature miRNA expression profiling	Cm1, Cm2	Cm1:miR-100/let-7a-2/miR-125b-1 cluster overexpression Cm2: miR-371–3 cluster overexpression	65
Hooks et al28	RNA	Transcriptomic	4-Gene signature gene expression profiling	C1, C2A, and C2B	C1: stronger diffused ITGA6 staining. C2A: upregulation of TOP2A, FA pathway activation. C2B: VIM organized into visible spindle-shaped structures.	39
Carrillo-Reixach et al29	DNA	Epigenetic variation	DNA hypomethylation and CpG island hypermethylation	Epi-CA and Epi-CB	Epi-CA: a weak global hypomethylation except for CpG islands compared with Epi-CB. Epi-CB: activation of Wnt/β- catenin signaling and a strong 14q32-gene signature.	113a
Sumazin et al30	DNA, RNA	Genomic and transcriptomic	Differential activation of hepatic progenitor cell markers and metabolic pathways	HB1, HB2, and HB3	HB1 (low risk): low expression of LIN28B and let-7; high expression of HNF1A. HB2 (high risk): high expression of NFE2L2, LIN28B, HMGA2, SALL4, AFP, oncofetal proteins and stem-cell markers. HB3 (intermediate-risk): situated between HB1 and HB2.	88

Abbreviations: AFP, α-fetoprotein; HMGA2, high mobility group AT-hook 2; HNF1A, hepatic nuclear factor 1 α; ITGA6, integrin α 6; let-7, lethal-7; LIN28B, lin-28 homolog B; NFE2L2, nuclear factor, erythroid 2–like 2; SALL4, spalt-like transcription factor 4; TOP2A, topoisomerase 2-α.

^a113 HBs (discovery set: 33 patients; validation set: 80 patients).