Table 1. Features of medulloblastoma subgroups.

Subtype	Molecular characteristics	Mutations	Age group
WNT activated	WNT pathway activation	CTNNB1 DDX3X Chromatin-remodeling genes TP53	Least common of subgroups Found in children and adults, not infants
SHH activated and TP53 wild- type	SHH pathway activation	PTCH1 SMO SUFU TERT promoter Chromatin-remodeling genes	Infants, children, and adults
SHH activated and TP53 mutant	SHH pathway activation	TP53	5–18 years old
Group 3	Elevated expression of MYC GABRA5 over-expression	SMARCA4 Chromatin-remodeling genes Genes of TGF-β pathway	Infants and children, not adults More common in boys than in girls
Group 4	Lmx1A expression	Chromatin-remodeling genes	More common in children than in adults Least common in infants

CTNNB1, catenin beta 1; DDX3X, DEAD-box helicase 3; Lmx1a, LIM homeobox transcription factor; PTCH1, Patched-1; SHH, sonic hedgehog; SMARCA4, SWI (switching)/SNF (sucrose non-fermenting)-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4; SMO, smoothened receptor; SUFU, suppressor of fused homolog protein; TERT, telomerase reverse transcriptase; TGF-β, transforming growth factor beta; TP53, tumor suppressor protein p53.