Pre-mRNA splicing is essential for intron removal and to increase the repertoire of gene products. If not properly regulated, mis-splicing can generate altered, potentially oncogenic proteins. Several cancers harbor monoallelic mutations of spliceosome factors while MYC-driven breast cancer exhibits an increase in precursor mRNA synthesis resulting in an increased burden on the spliceosome and sensitivity to spliceosome inhibition. In a recent study, we could show that high expression levels of spliceosome factors are closely correlated with high-risk NB and poor clinical outcome. In addition, we were able to target the spliceosome and inhibit tumor growth in a xenograft NB model utilizing spliceosome inhibitors. We will now through ONT analyze the consequences of splicesome inhibiton on the expression of splice isoforms in neuroblastoma xenografts.