New Pan Trk antibody, clone EPR17341
The family of neurotrophic tyrosine kinase (NTRK1/2/3) genes encodes the TrkA, TrkB and TrkC protein kinases. The three family members are activated by different neurotrophins like NGF (nerve growth factor), BDNF (brain-derived neurotrophic factor), NT-4 (neurotrophin-4), and NT-3 (neurotrophin-3). Neurotrophin signalling activates cellular pathways involved in the development and maturation of the central and peripheral nervous systems through regulation of proliferation, differentiation, and survival of sympathetic and nervous neurons.
Fusions of the receptor tyrosine kinases genes NTRK1, NTRK2 and NTRK3, which result in overexpressed and constitutively active Trk fusion proteins, are present in a variety of different malignancies. NTRK fusions with various partners are highly recurrent in certain rare malignancies, such as secretory carcinoma of the breast or salivary gland and infantile fibrosarcoma, but they are also infrequently seen in some common cancers, such as melanoma, glioma and carcinomas of the thyroid, lung and colon. Expression of the wild-type Trk protein is seen in some neuroendocrine tumors but is absent or extremely low in most solid tumors. Entrectinib is an effective inhibitor of Trk A/B/C receptor tyrosine kinases, which can also be used in patients with CNS tumors or -metastases. With the approval of the Trk inhibitor larotrectinib for patients with non-hematologic tumors, the assessment of NTRK fusion became a routine method for patients with locally advanced or metastatic cancers . Several studies using Pan Trk antibodies on different tumor tissues showed a high sensitivity and specificity for NTKR fusions ranging from 79 % to 100 % respectively. Only for sarcomas, sensitivity as well as specificity of an immunohistochemical Pan Trk test seems to be rather low [1-3]. The European Society for Medical Oncology (ESMO) therefore recommends either front-line sequencing (preferentially RNA-sequencing) or immunohistochemistry as methods for screening, especially in tumors where NTRK1/2/3 fusions are uncommon . We now offer the rabbit monoclonal primary antibody EPR17341 which is directed against a common part of the C-terminal region of the Trk proteins.
 Solomon JP et al. NTRK fusion detection across multiple assays and 33,997 cases: diagnostic implications and pitfalls. Mod Pathol. 33:38-46, 2020
 Hechtman J et al. Pan-Trk Immunohistochemistry Is an Efficient and Reliable Screen for the Detection of NTRK Fusions. Am J Surg Pathol. 41:1547–1551, 2017
 Rudzinski ER et al. Pan-Trk immunohistochemistry identifies NTRK rearrangements in pediatric mesenchymal tumors. Am J Surg Pathol 2018, 42:927-935
 Marchiò C et al. ESMO recommendations on the standard methods to detect NTRK fusions in daily practice and clinical research. Ann Oncol. 301417-1427, 2019