{Reference Type}: Journal Article {Title}: NTRK fusions in lung cancer: From biology to therapy. {Author}: Harada G;Santini FC;Wilhelm C;Drilon A; {Journal}: Lung Cancer {Volume}: 161 {Issue}: 0 {Year}: 11 2021 {Factor}: 6.081 {DOI}: 10.1016/j.lungcan.2021.09.005 {Abstract}: Fusions involving TRK protein tyrosine kinases are oncogenic drivers in a variety of tumors in children and adults, with a prevalence of ∼0.2% in non-small cell lung cancer. Diagnosis can be challenging due to structural features such as NTRK intron length, but next-generation sequencing (NGS), including RNA-based NGS, increases detection. The first-generation TRK inhibitors, larotrectinib and entrectinib, have demonstrated clinically meaningful antitumor activity in TRK fusion-positive cancers in a tumor-agnostic fashion and should be considered first-line therapeutic options for TRK fusion-positive lung cancers. Furthermore, the first-generation TRK inhibitors are well tolerated. Care should be taken, however, to monitor on-target adverse events, such as dizziness, weight gain, paresthesias, and withdrawal pain. On-target and off-target mechanisms mediating TRK inhibitor resistance may occur. Next-generation TRK inhibitors, such as selitrectinib, repotrectinib, and taletrectinib, are available on ongoing clinical trials and address on-target resistance. This review will focus on NTRK fusions and TRK-directed targeted therapy specifically in the context of lung cancer.