The epithelial cell adhesion molecule (EpCAM) is a membrane glycoprotein that is highly expressed on most carcinomas and therefore of potential use as a diagnostic and prognostic marker for a variety of carcinomas. Interestingly, EpCAM is explored as target in antibody-based therapies. Recently, EpCAM has been identified as an additional marker of cancer-initiating cells. In this review, we describe the controversial biological role of EpCAM with the focus on carcinogenesis: as an adhesion molecule, EpCAM mediates homophilic adhesion interactions, which in turn might prevent metastasis. On the other hand, EpCAM abrogates E-cadherin mediated cell-cell adhesion thereby promoting metastasis. Also, upon cleavage of EpCAM, the intracellular domain functions as a part of a transcriptional complex inducing c-myc and cyclin A and E. In line with these seemingly controversial roles, EpCAM overexpression has been associated with both decreased and increased survival of patients. Similarly, either induction or downregulation of EpCAM expression lowers the oncogenic potential depending on the cell type. As epigenetic dysregulation underlies aberrant EpCAM expression, we propose epigenetic editing as a novel approach to investigate the biological role of EpCAM, expanding the options for EpCAM as a therapeutic target in cancer.

Patients with pT1cN0 oral squamous cell carcinomas (OSCC) are generally not treated with a neck dissection (ND). However, in 25% of cN0 patients, nodal metastases become apparent during follow-up. Infiltration depth of the primary tumour has been consistently associated with the presence of nodal metastasis, but proposed cut-off depths for performing a ND vary considerably. The aim of this study was to explore the infiltration depth as predictor for the nodal status and to recommend a cut-off depth for performing a ND. From our database of 351 primary oral carcinomas, we selected all pT1-2 tumours (n=246). Infiltration depth was measured in 212 cases. Neck status was determined by histopathological examination of the dissection specimen, or by at least two years of follow-up. Mean infiltration depth was 5.49 mm (95% CI: 4.86-6.12) in the N0 and 8.40 mm (95% CI: 7.38-9.43) in the N+ group (p<0.001). cN status, lymphovascular invasion and infiltration depth were the only independent predictors for nodal status in multiple logistic regression. ROC-analysis on pT1cN0 tumours resulted in an optimal cut-off for the prediction of the nodal status at a depth of 4.59 mm. This cut-off identified a subgroup of patients at increased risk for nodal metastasis (OR=8.3) and with significantly shorter survival. Tumour infiltration depth is an independent predictor for nodal status in pT1-2 OSCC. In pT1cN0 tumours, a cut-off at 4.59 mm results in the best predictive value. We recommend an infiltration depth of ≥4 mm as an indication to perform a neck dissection in pT1cN0 OSCC.

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