Prevalence of HER-2 expression and correlation with clinicopathological features in gynecological cancer: A single-center retrospective study in China.

Abstract

e17500 Background: Targeted therapy for human epidermal growth factor receptor 2 (HER2) has become a standard of care in several HER2-expressing solid tumors. Nonetheless, there remains an unmet need for effective treatment, for instance, anti-HER2 antibody-drug conjugates (ADCs), in advanced stage gynecological cancer. In this context, we presented a retrospective study on the incidence of HER2 expression in primary gynecological cancer based on a single-center data from southwestern China. Methods: Paraffin-embedded tumor tissue blocks, clinicopathological, and survival data of gynecological cancer patients were collected from Chongqing University Cancer Hospital. HER2 IHC scoring was carried out according to the updated ASCO/CAP guidelines for breast and gastroesophageal adenocarcinoma by two pathologists independently. Data analysis was performed using SPSS v.24. Results: A total of 104 cases of cervical cancer, 102 cases of endometrial cancer and 103 cases of ovarian cancer were included between 2019 and 2023. HER2 expression was detected in 31.7% samples, with scores of 1+, 2+, and 3+ in 23.9% (74/309: 36/104, 16/102, 22/103), 5.8% (18/309: 7/104, 7/102, 4/103), and 1.9% (6/309: 2/104, 1/102, 3/103) of patients, respectively. Notably, ultra-low HER2 expression with incomplete and faint staining in ≤10% of tumor cells was observed in 41.1% (127/309: 37/104, 53/102, 37/103) of patients. Metastasis and lymphovascular invasion were associated with elevated HER2 expression in endometrial cancer (p=0.037, 0.040, respectively), while a larger tumor size was associated with elevated HER2 expression in cervical cancer (p=0.004). However, no positive association between HER2 status and overall survival (OS) was found in cervical, endometrial or ovarian cancer. In our cohort, metastasis was the only risk factor related to reduced OS of gynecological cancer patients by COX regression analysis (HR=14.00, 95%CI=1.32-148.21, p=0.028). Conclusions: Our data revealed a considerable number of patients with HER2-low and ultra-low gynecological cancer. It might represent a significant portion in real-world scenarios and warrant more consideration in selecting candidates for HER2-targeted ADCs, especially for those with relapsed or refractory conditions. Given the inherent challenge in interpretation, the study highlights the necessity for a consensus on evaluating HER2 immuno-staining results in gynecological cancer. Clinical trial information: MR-50-23-019676 . [Table: see text]