RB1 and neoplasm: Although DAM and MFB are desmin-positive tumours, these tumours harbour a different molecular signature; the former is often HMGA2-positive, as a surrogate of HMGA2 rearrangements, while the latter shows the absence of RB1 nuclear expression and the overexpression of CY2E1, respectively, as a surrogate of the 13q14 deletion and MTG1–CYP2E1 fusion transcripts [5].