Deep sequencing analysis of circulating tumor DNA (ctDNA) enriched for the EGFR L858R mutation revealed a significant presence of EGFR L858R ctDNA as ultrashort ctDNA (usctDNA) with sizes ranging from 40 to 60 base pairs in patient plasma and saliva, with the majority of usctDNAs predominantly localized within the exosomal fraction (Wang F. et al., 2024). The gene discussed is EGFR; the disease is neoplasm.