NTRK1 and digestive system neoplasm: Two (0.3%) of 711 patients with ductal infiltrating breast carcinomas were found to be positive for NTRK1 gene fusions (Figure 3) as well as a patient (0.8%) in a series of 132 cases with lung adenocarcinoma, 2 (1.3%) of 159 patients with gastrointestinal tumors, specifically a colorectal carcinoma and a gastrointestinal stromal tumor (GIST).