Targeting EpCAM expression via near-infrared fluorescent antibodies enables microscopic delineation of primary and recurrent HNSCC.

BACKGROUND

In surgical treatment of head and neck squamous cell carcinoma (HNSCC), resection with adequate tumor-free margins is a fundamental challenge. Epithelial cell adhesion molecule (EpCAM/CD326) is substantially overexpressed in HNSCC representing a potential target for fluorescence-guided delineation of HNSCC.

MATERIALS AND

METHODS

EpCAM expression was assessed in vitro on squamous cell carcinomas of the upper aerodigestive tract (SCC-UADT) and fibroblasts employing immunostaining with anti-EpCAM antibodies VU1D9 and MT201/adecatumumab (clinically validated). Whole tumor analyses of EpCAM expression were conducted in patient samples with primary and recurrent HNSCC. Confocal microscopy was used for EpCAM expression analyses upon immunostaining in cultured patient HNSCC resection samples using IRDye800CW-labeled MT201.

RESULTS

Immunostaining with VU1D9 and MT201 revealed a high, consistent, and specific expression of EpCAM on SCC-UADT in vitro. Human whole tumor analyses showed high and consistent EpCAM expression (primary: 9/9 > = 80%; recurrent: 6/9 > = 80%) and significantly elevated near-infrared fluorescence intensities for IRDye800CW-VU1D9 and IRDye800CW-MT201 in HNSCC as compared to non-malignant tissue (2-7 fold vs. mucosa; 6-20 fold vs. HNSCC-associated stroma). Translational postoperative immunostaining of live cultured patient HNSCC samples using the clinically validated IRDye800CW-MT201/adecatumumab enabled microscopical differentiation of HNSCC from adjacent non-malignant tissue (fluorescence intensity ratios HNSCC vs. mucosa: 7,66 ± 1,26; and vs. HNSCC-associated stroma: 50,97 ± 8,24)).

CONCLUSIONS

IRDye800CW-labeled anti-EpCAM antibodies allow experimental microscopic delineation of HNSCC from non-malignant tissue. As a future outlook, these probes might improve tumor resection in near-infrared fluorescence-guided surgery of primary and recurrent HNSCC.