For instance, while morphological and IHC evaluation might be sufficient to establish the concordance between a putative 3D model and the original patient sample for chordoma cases using brachyury IHC assessment, fluorescent in situ hybridization (FISH) would be required to confirm the presence of a YAP1-TFE3 rearrangement in a case of non-CAMTA1-rearranged epithelioid hemangioendothelioma (EHE), both in the patient’s original sample and in the putative EHE 3D culture. The gene discussed is TBX1; the disease is chordoma.