Establishment and characterization of NCC-DSM1-C1: a novel cell line derived from a patient with desmoid fibromatosis.

Desmoid fibromatosis (DSM) is a rare, locally aggressive mesenchymal tumor genetically characterized by mutations in the CTNNB1 gene. A local control rate of up to 65‒80% for DSM is achieved with multiple modality treatments, including watchful monitoring, radiation therapy, chemotherapy, and surgery. However, several variables, such as age < 30 years, extremity tumor location, and tumor size of > 10 cm in diameter, are associated with poor local control rates in patients with DSM. The definitive treatments for DSM have not been established. Therefore, it is necessary to develop novel treatments for DSM. Moreover, although patient-derived tumor cell lines are potent tools for preclinical research, no DSM cell lines have been reported. Therefore, this study aimed to establish and characterize a novel DSM cell line for preclinical studies on DSM. Herein, we established the first cell line derived from a patient with DSM exhibiting poor prognostic factors (27-year-old male patient with a DSM tumor of > 10 cm in diameter located at the lower extremity) and named it NCC-DSM1-C1. NCC-DSM1-C1 cells had a T41A mutation in CTNNB1 and exhibited constant proliferation, spheroid formation, and invasion capability in vitro. Screening of antitumor agents in NCC-DSM1-C1 cells showed that bortezomib and romidepsin are effective against DSM. In conclusion, we report the first officially characterized DSM cell line derived from a patient with DSM exhibiting factors associated with poor prognosis. We believe that NCC-DSM1-C1 cell line is a useful tool for developing novel treatments for DSM.