Circulating Tumor Cells Detected Using EpAb3-5 as Prognostic Indicators in Head and Neck Squamous Cell Carcinoma

EpAb3-5, an anti-EpCAM (epithelial cell adhesion molecule) neutralizing antibody, enhances circulating tumor cell (CTC) detection, but its clinical and prognostic relevance in head and neck squamous cell carcinoma (HNSCC) remains unclear.

We retrospectively analyzed 66 HNSCC patients. CTCs were enumerated using EpAb3-5 and a commercial EpCAM-based platform (MACS), and tumor EpCAM expression detected using EpAb3-5 was assessed by immunohistochemistry. Associations with clinicopathologic features were evaluated, and survival outcomes were analyzed using Kaplan-Meier and Cox regression models, truncated at five years.

EpAb3-5 detected significantly more CTCs than MACS (p < 0.001), indicating greater detection sensitivity. Tumor EpCAM expression detected by EpAb3-5 correlated with nodal status (p < 0.01) but not T classification or overall stage. Although EpAb3-5-detected EpCAM expression alone was not an independent predictor of overall survival (OS) or disease-free survival (DFS), its integration with tumor staging revealed a context-dependent prognostic association. Specifically, low EpCAM expression assessed using EpAb3-5 identified early-stage patients with better OS (p < 0.05), whereas no significant survival differences were observed in advanced-stage disease.

EpAb3-5 enhances CTC detection compared with a conventional EpCAM-based method and provides complementary prognostic information when interpreted alongside tumor staging. These findings indicate that EpCAM immunoreactivity assessed using EpAb3-5 may assist in refining risk stratification in early-stage HNSCC; however, these observations should be considered exploratory and warrant further validation in larger prospective cohorts.