ETV6 and cancer: Previously, the TRK protein inhibitor Larotrectinib was used to treat a pediatric patient diagnosed with an ETV6-NTRK3 fusion-positive secretory breast carcinoma.28 Recent data from multiple clinical trials using Larotrectinib further bolster its utility in the treatment of TRK fusion-positive cancer, with 121 (79.1%) of 153 patients demonstrating an objective response, with 24 (15.7%) having a complete response.29 Furthermore, a variety of tumor types harbor the ETV6-NTRK3 fusion protein, thus providing additional targets for future TRK inhibition therapy.30