Cancer genome profiling of prostate cancer identifies a patient with a novel EFNA1-NTRK1 fusion gene.

NTRK gene fusions serve as oncogenic drivers in solid tumors. While these fusions are uncommon in prostate cancer, they can be detected through cancer genome profiling tests. In a study of 68 prostate cancer cases analyzed with comprehensive cancer genome profiling, we identified a single instance of a novel EFNA1-NTRK1 fusion. The patient, a 56-year-old male diagnosed with prostate cancer and bone metastasis, presented with an initial PSA level of 323 ng/mL, a Gleason score of 4 + 4, and was classified as cT3bN0M1b. He underwent combined androgen blockade therapy but progressed to castration-resistant prostate cancer after 31 months. Despite previous treatments with androgen receptor signaling inhibitors and chemotherapies, the cancer continued to advance. Following the identification of an EFNA1-NTRK1 gene fusion via a cancer genome profiling test, the patient received treatment with larotrectinib. Although the initial biopsy showed positive pan-TRK staining in the prostate cancer tissue, the response to larotrectinib was limited in this case.