RXRG and neoplasm: Immunostaining revealed that retinoid X receptor-γ (RXRγ) and thyroid hormone receptor β2 (TRβ2), transcription factors important for the differentiation and maintenance of M/L cone identity34,35, were detected in a majority of tumor cells within tissues and organoids (Figs 2g–h’, S1d−e’ and S2d−e’).