Widespread folate receptor expression in pediatric and adolescent solid tumors - opportunity for intraoperative visualization with the novel fluorescent agent pafolacianine.

Contemporary fluorescence-guided surgery has evolved principally based on the uses and limitations of the contrast agent indocyanine green (ICG). A second generation of novel fluorescent agents are under development to target specific molecular markers on tumor cells and/or the tumor micro-environment. Pafolacianine, a molecular agent targeting the folate receptor (FR), is the first of these approved for use in adults, but its potential utility in pediatric cancers is unknown. In this study, we performed immunohistochemistry staining on slides obtained from a range of pediatric patients with solid tumors. Slides were stained with antibodies to FRα and FRβ, and fluorescence was quantified. Separately, publicly available RNA sequencing data were queried for both FRα and FRβ expression in various pediatric tumors.