Spatial and graded heterogeneity of GD2 expression in neuroblastoma revealed by whole-slide immunohistochemistry

Anti-GD2 immunotherapy has improved outcomes in high-risk neuroblastoma; however, therapeutic responses remain heterogeneous. Although GD2 is generally assumed to be uniformly expressed in neuroblastoma, its spatial distribution within clinical tumors has not been systematically characterized. We therefore investigated intratumoral GD2 heterogeneity using whole-slide immunohistochemistry and explored its molecular regulation. GD2 expression was evaluated in 45 FFPE neuroblastoma tumors using standardized whole-slide immunohistochemistry and independently assessed by two pathologists. GD2 surface expression was analyzed by flow cytometry in 12 neuroblastoma cell lines. Functional roles of ganglioside biosynthetic enzymes were evaluated using siRNA-mediated knockdown. Whole-slide immunohistochemistry demonstrated frequent intratumoral GD2 heterogeneity. Fourteen tumors (31%) contained