Tropomyosin receptor kinase C (NTRK3) G696A (TRKC G696A)

Tropomyosin receptor kinase C (TRKC) G696A is a clinically significant point mutation located in the xDFG motif of the NTRK3 kinase domain (UniProt P35732). TRKC normally functions as a receptor for neurotrophin-3 (NT-3) and plays a vital role in the development and maintenance of the nervous system. This specific substitution of glycine with alanine at residue 696 is a well-documented mechanism of acquired resistance in patients with NTRK3 fusion-positive cancers undergoing treatment with first-generation TRK inhibitors such as larotrectinib and entrectinib (Drilon et al., 2018, Cancer Discovery). The G696A mutation introduces a bulkier side chain that sterically hinders the binding of these inhibitors within the ATP-binding pocket, thereby restoring oncogenic signaling and leading to tumor progression (Russo et al., 2020, Annals of Oncology). To address this challenge, next-generation TRK inhibitors like selitrectinib and repotrectinib have been developed with macrocyclic or compact structures that can accommodate the G696A mutation (Cocco et al., 2018, Nature Medicine). Monitoring for this mutation via liquid biopsy or repeat tumor sequencing is essential for guiding subsequent lines of therapy in NTRK-driven malignancies (NCCN Guidelines, 2023).

Other names

NTRK3 G696ANeurotrophic tyrosine kinase receptor type 3 G696ATRKC xDFG mutation G696A

ATP-competitive inhibition of the TRKC kinase domain to block downstream oncogenic signaling pathways such as MAPK/ERK, PI3K/AKT, and PLC-gamma.