The aims of the present study were to characterize MRPS23 copy number alterations by fluorescence in situ hybridization (FISH) on formalin-fixed, paraffin-embedded (FFPE) primary tumour tissue and corresponding lymph node metastases from this cohort, and to assess how these copy number alterations associates with molecular subtypes, proliferation and prognosis. The gene discussed is MRPS23; the disease is neoplasm.