ERBB2 and metastatic neoplasm: Since NTRK fusions are considered to be mutually exclusive, NTRK gene fusion testing should be ideally be considered as part of a larger molecular panel testing for ALK, ROS1, EGFR, KRAS, RET, BRAF, ERBB2 exon 20, NRG1 and MET. The Canadian consensus recommends integration of routine testing for NTRK1-3 genes in Stage III/IV patients with locally advanced or metastatic disease, in patients with non-squamous or adenocarcinoma components.