SEMA6A and ganglioneuroma: In this cohort, the three SHHa tumors (MB002, MB009, and MB019) are primarily composed of GLI2+ cells and SEMA6A+ cells resembling earlier stages of GN development, whereas all three SHHb tumors (MB005, MB015, and MB084) contain a large proportion of GABRD+ cells that resemble late-stage GNs (Supplementary Fig. 8).