BCYRN1 and neoplasm: Moreover, confocal microscopy analysis was conducted to reveal the significant enrichment of exosomes in LYVE1‐indicated lymphatic endothelial cells in the mice footpad primary tumor tissues intratumorally injected with PKH67‐labelled UM‐UC‐3‐EXOBCYRN1 (Figure S8A), further confirming the uptake of exosomal BCYRN1 by lymphatic endothelial cells in vivo.