Spatial transcriptomic analysis of Sonic Hedgehog Medulloblastoma identified that loss of heterogeneity and promotion of differentiation underlies the response to CDK4/6 inhibition

We used spatially resolved transcriptomics to define the cellular diversity within a sonic hedgehog (SHH) patient-derived model of Medulloblastoma (MB) and identify how cells specific to a transcriptional state or spatial location are pivotal in responses to treatment with the CDK4/6 inhibitor, Palbociclib. Our analysis reveals that SHH tumour in the mouse brain contains multiple malignant transcriptional states, recapitulating the extent of intratumoural cellular diversity identified in primary human SHH MB. Our study offers new insight into the previously described features of CDK4/6 inhibition in MB, with Palbociclib treatment inducing neuronal differentiation across all remaining cell types comprising the bulk of the SHH patient-derived orthotropic xenograft model. This study is, to the best of our knowledge, the first spatially resolved gene expression atlas of SHH PDOX MB and acts as proof-of-principle for the use of ST-seq in identifying spatially-organised tumour heterogeneity of MB.