HER2 mutations in advanced cervical neuroendocrine carcinoma: implications for trastuzumab deruxtecan therapy.

Recent clinical evidence shows that the antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) can successfully treat patients with advanced HER2-mutant non-small cell lung cancer (NSCLC). We aimed to characterize HER2 mutations in cervical neuroendocrine carcinoma (NEC) among Taiwanese women to provide the rationale for exploring T-DXd as a tumor-agnostic targeted therapy option. We analyzed 12 archived primary cervical NEC samples from Taiwanese patients. Tumor-rich areas were marked for microdissection on 10 μm unstained sections. DNA was extracted, and HER2 hotspots were sequenced using a targeted panel on the Illumina MiSeq. HER2 missense mutations were identified in 5 of 12 cases (41.7%). Of the 5 cases with mutations, 2 patients (40%) had a single mutation, while 3 patients (60%) had double mutations. We detected 4 substitutions outside the tyrosine kinase domain (non-TKD), which were p.P1170A, p.S305C, p.I655V, and a novel T328K alteration. No mutations were found within the tyrosine kinase domain (TKD). The 41.7% HER2 mutation rate warrants expanded screening and future clinical investigation of the T-DXd targeting HER2 mutations in cervical NEC patients. Overall, this study contributes to the molecular understanding of cervical NEC and lays the groundwork for developing more effective treatment strategies.