SHH and central nervous system neoplasm: According to the World Health Organization (WHO) classification of CNS tumors, the following four major subgroups have been identified based on molecular and genetic characteristics: wingless (WNT)-activated, sonic hedgehog (SHH)-activated, and numerically designated non-WNT/non-SHH, representing Groups 3 and 4 (Louis et al., 2016; Northcott et al., 2019; Louis et al., 2021).