Clinicopathological Characteristics of NRG1 Fusion-Positive Solid Tumors in Korean Patients.

PURPOSE: Neuregulin 1 (NRG1) gene fusion is a potentially actionable oncogenic driver. The oncoprotein binds to ERBB3-ERBB2 heterodimers and activates downstream signaling, supporting a therapeutic approach for inhibiting ERBB3/ERBB2. However, the frequency and clinicopathological features of solid tumors harboring NRG1 fusions in Korean patients remain largely unknown.

MATERIALS AND

METHODS

We reviewed archival data from next-generation sequencing panel tests conducted at a single institution, specifically selecting patients with in-frame fusions that preserved the functional domain. The clinicopathological characteristics of patients harboring NRG1 fusions were retrospectively reviewed.

RESULTS

Out of 8,148 patients, NRG1 fusions were identified in 22 patients (0.27%). The average age of the patients was 59 years (range, 32 to 78 years), and the male-to-female ratio was 1:1.2. The lung was the most frequently observed primary site (n=13), followed by the pancreaticobiliary tract (n=3), gastrointestinal tract (n=2, stomach and rectum each), ovary (n=2), breast (n=1), and soft tissue (n=1). Histologically, all tumors demonstrated adenocarcinoma histology, with the exception of one case of sarcoma. CD74 (n=8) and SLC3A2 (n=4) were the most frequently identified fusion partners. Dominant features included the presence of fewer than three co-occurring genetic alterations, a low tumor mutation burden, and low programmed death-ligand 1 expression. Various clinical responses were observed in patients with NRG1 fusions.

CONCLUSION

Despite the rarity of NRG1 fusions in Korean patients with solid tumors, identification through next-generation sequencing enables the possibility of new targeted therapies.