Cell-free Tumor DNA in Bronchoalveolar Lavage- a proof of concept study

<title>Extract</title> Molecular analysis is increasingly integral to lung cancer evaluation and management [1]. While evidence of circulating tumor DNA (ctDNA) has existed for decades [2], research in this field centers on ctDNA detection primarily in peripheral blood, which may present limitations. These include reduced sensitivity [3, 4], the potential of false negatives due to low tumor burden or shedding [5], and the possibility that lung compartmentalization may prevent cancer cells from appearing in systematic circulation [6]. We hypothesized that bronchoalveolar lavage (BAL) would exhibit an enrichment of lung cancer-derived cell-free DNA (cfDNA) detectable using digital PCR (dPCR), a precise method for nucleic acid quantification.