Chen W and colleagues focused on the practical issues regarding MMR-IHC reporting and interpretation, paying particular care to the cutoff for normal staining, the staining variability/patchiness, the staining intensity of the tumor weaker than the control, the staining pattern post neoadjuvant therapy and the cytoplasmatic staining potentially associated with EPCAM-MSH2 fusion [39]. The gene discussed is MSH2; the disease is neoplasm.