ARR3 and neoplasm: Immunohistochemical analysis of this tumor showed a mutually exclusive expression of ARR3 and EBF3, defining two types of areas (CRX+/ARR3+/EBF3− and CRX+/ARR3−/EBF3+) (Supplementary Fig. 5a), as observed in about 30% of subtype 2 tumors.