S1PR2 and neoplasm: Interestingly, targeted sequencing of 13 selected variants in the circulating tumor DNA (ctDNA) sample at transformation detected mutations that were clonal and shared between the spatial biopsies (CREBBP, KMT2D, EP300, and TNFRSF14), but failed to recover all the site-specific variants in the tLN (e.g., EBF1 and S1PR2 corrected VAFs: 21.7% and 38.7%, respectively), indicating that different tumor subpopulations dynamically circulate in the plasma and that ctDNA may not invariably capture the entire genetic spectrum, and warrants further exploration (Figure S5).