High-throughput sequencing detection and ensartinib treatment of lung cancer harboring NTRK1 fusion

Dear Editor,Although fusion events involving neurotrophic receptor tyrosine kinase 1,2,and 3 genes(NTRK1,NTRK2,and NTRK3,encoding TRKA/B/C respectively)were found in diverse tumor types,only 0.1%-0.3%of lung cancer patients harbor an NTRK(and mostly NTRK1)fusion as the primary oncogenic event[1].Such low prevalence may be partially due to the limited availability of first-line assays for detecting rare fusion events[2].Immunohistochemistry is limited by sensitivity and variable tissue background,and fluorescence in-situ hybridization falls short of elucidating functional significance such as the identity of the partner or structure of the transcript.While DNA next-generation sequencing(NGS)is suitable for mutation calling(single nucleotide variation[SNV]and insertion-or-deletion[indel]),and RNA NGS is particularly effective in detecting fusions[3],routinely performing these two assays together is labor-intensive.As a solution,we have developed a single NGS assay(PANO-Seq)for unified RNA/DNA target enrichment library preparation[4],which takes about 12 hours and $10 to prepare.