GNGT2 and retinoblastoma: To identify major cell types in human retinoblastoma, cells-specific genes were used to annotate cell types with classic markers described in previous studies [11, 21]: cone precursors (GNGT2, RXRG, CRX, PDE6H) and retinoblastoma cells (MKI67, CDK1, TOP2A, KIF14, CDC25C).