An Ep-ICD based index is a marker of aggressiveness and poor prognosis in thyroid carcinoma

EpEX, the soluble extracellular domain of EpCAM, resists cetuximab treatment of EGFR-high head and neck squamous cell carcinoma

OBJECTIVES

Cetuximab (Cmab) is a molecularly targeted monoclonal antibody drug for head and neck squamous cell carcinoma (HNSC), although cetuximab resistance is a serious challenge. Epithelial cell adhesion molecule (EpCAM) is an established marker for many epithelial tumors, while the soluble EpCAM extracellular domain (EpEX) functions as a ligand for epidermal growth factor receptor (EGFR). We investigated the expression of EpCAM in HNSC, its involvement in Cmab action, and the mechanism by which soluble EpEX activated EGFR and played key roles in Cmab resistance.

MATERIALS AND METHODS

We first examined EPCAM expression in HNSCs and its clinical significance by searching gene expression array databases. We then examined the effects of soluble EpEX and Cmab on intracellular signaling and Cmab efficacy in HNSC cell lines (HSC-3 and SAS).

RESULTS

EPCAM expression was found to be enhanced in HNSC tumor tissues compared to normal tissues, and the enhancement was correlated with stage progression and prognosis. Soluble EpEX activated the EGFR-ERK signaling pathway and nuclear translocation of EpCAM intracellular domains (EpICDs) in HNSC cells. EpEX resisted the antitumor effect of Cmab in an EGFR expression-dependent manner.

CONCLUSION

Soluble EpEX activates EGFR to increase Cmab resistance in HNSC cells. The EpEX-activated Cmab resistance in HNSC is potentially mediated by the EGFR-ERK signaling pathway and the EpCAM cleavage-induced nuclear translocation of EpICD. High expression and cleavage of EpCAM are potential biomarkers for predicting the clinical efficacy and resistance to Cmab.

Epithelial Cell Adhesion Molecule in Primary Sjögren's Syndrome Patients: Characterization and Evaluation of a Potential Biomarker

Objective

To determine the subcellular localization of epithelial cell adhesion molecule (EpCAM) in labial salivary gland (LSG) and evaluate the diagnostic use of the extracellular domain of EpCAM (EpEX) and intracellular domain (EpICD) for primary Sjögren's syndrome (pSS).

Methods

Immunohistochemical (IHC) analysis was conducted using EpEX and EpICD domain-specific antibodies on labial salivary gland biopsy (LSGB) from participants. Chi-square or Fisher's exact analysis, Mann-Whitney U-test, and Kruskal-Wallis test compared differences among groups. Independent risk factors of pSS were determined by multiple logistic regression analysis. Receiver-operator characteristic curves (ROC) were carried out to estimate the diagnostic value.

Results

Compared to non-SS controls, loss of membranous EpEX and EpICD expression was observed in LSGB of pSS patients, which occurred in parallel with increased accumulation of cytoplastic and nuclear EpICD. The subcellular EpEX/EpICD expressions were associated with various features of pSS patients, especially histopathological grade of LSGB. Furthermore, high IHC scores of membranous EpEX were independent risk factors for pSS, even for the pSS patients at early stage. The IHC scores of subcellular EpEX/EpICD were of great diagnostic value for pSS with high sensitivity (70-80%) and specificity (85-95%).

Conclusion

This study first found the aberrant expression pattern of EpCAM in LSG of pSS patients. The IHC scores of subcellular EpEX/EpICD were demonstrated to have the potential to act as diagnostic biomarkers for pSS.

Programmed death-ligand 1 expression by digital image analysis advances thyroid cancer diagnosis among encapsulated follicular lesions

Recognition of noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) that distinguishes them from invasive malignant encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) can prevent overtreatment of NIFTP patients. We and others have previously reported that programmed death-ligand 1 (PD-L1) is a useful biomarker in thyroid tumors; however, all reports to date have relied on manual scoring that is time consuming as well as subject to individual bias. Consequently, we developed a digital image analysis (DIA) protocol for cytoplasmic and membranous stain quantitation (ThyApp) and evaluated three tumor sampling methods [Systemic Uniform Random Sampling, hotspot nucleus, and hotspot nucleus/3,3'-Diaminobenzidine (DAB)]. A patient cohort of 153 cases consisting of 48 NIFTP, 44 EFVPTC, 26 benign nodules and 35 encapsulated follicular lesions/neoplasms with lymphocytic thyroiditis (LT) was studied. ThyApp quantitation of PD-L1 expression revealed a significant difference between invasive EFVPTC and NIFTP; but none between NIFTP and benign nodules. ThyApp integrated with hotspot nucleus tumor sampling method demonstrated to be most clinically relevant, consumed least processing time, and eliminated interobserver variance. In conclusion, the fully automatic DIA algorithm developed using a histomorphological approach objectively quantitated PD-L1 expression in encapsulated thyroid neoplasms and outperformed manual scoring in reproducibility and higher efficiency.

Programmed death-ligand 1 overexpression is a prognostic marker for aggressive papillary thyroid cancer and its variants

Programmed death-ligand 1(PD-L1) expression on tumor cells is emerging as a potential predictive biomarker in anti-PD-L1 directed cancer immunotherapy. We analyzed PD-L1 expression in papillary thyroid carcinoma (PTC) and its variants and determined its prognostic potential to predict clinical outcome in these patients. This study was conducted at an academic oncology hospital which is a prime referral centre for thyroid diseases. Immunohistochemical subcellular localization (IHC) analyses of PD-L1 protein was retrospectively performed on 251 archived formalin fixed and paraffin embedded (FFPE) surgical tissues (66 benign thyroid nodules and 185 PTCs) using a rabbit monoclonal anti-PD-L1 antibody (E1L3N, Cell Signaling Technology) and detected using VECTASTAIN rapid protocol with diaminobenzidine (DAB) as the chromogen. The clinical-pathological factors and disease outcome over 190 months were assessed; immunohistochemical subcellular localization of PD-L1 was correlated with disease free survival (DFS) using Kaplan Meier survival and Cox multivariate regression analysis. Increased PD-L1 immunostaining was predominantly localized in cytoplasm and occasionally in plasma membrane of tumor cells. Among all combined stages of PTC, patients with increased PD-L1 membrane or cytoplasmic positivity had significantly shorter median DFS (36 months and 49 months respectively) as compared to those with PD-L1 negative tumors (DFS, both 186 months with p < 0.001 and p < 0.01 respectively). Comparison of PD-L1⁺ and PD-L1⁻ patients with matched staging showed increased cytoplasmic positivity in all four stages of PTC that correlated with a greater risk of recurrence and a poor prognosis, but increased membrane positivity significantly correlated with a greater risk of metastasis or death only in Stage IV patients. In conclusion, PD-L1 positive expression in PTC correlates with a greater risk of recurrence and shortened disease free survival supporting its potential application as a prognostic marker for PTC.

Detection and Prognostic Significance of Circulating Tumor Cells in Patients With Metastatic Thyroid Cancer

CONTEXT

Individual patient prognostication for advanced thyroid cancer (TC) is challenging. Circulating tumor cells (CTCs) have been shown to be a valuable prognostic marker for other solid cancers.

OBJECTIVE

We hypothesized that CTCs are present in the blood of patients with advanced TC and their number can predict overall survival (OS).

SETTING

This is a prospective study at a tertiary cancer hospital. Patients, Interventions, and Main Outcome Measures: Initial studies were performed with TC cell lines to determine the feasibility of detection using the Veridex CellSearch. CTC enumeration was performed in blood samples from 18 patients with distantly metastatic medullary TC (metMTC), 14 with distantly metastatic differentiated TC (metDTC), and 10 controls with a history of TC but no evidence of disease. The prognostic value of CTC levels to predict OS in metMTC patients was assessed.

RESULTS

CellSearch detected cells from MTC and DTC but not anaplastic TC cell lines. Six metMTC patients but no metDTC or control patients had more than or equal to 5 CTCs detected by the CellSearch assay. Median survival in metMTC patients with more than or equal to 5 CTCs was 13 months vs 51.5 months for those with less than 5 CTCs (P = .0116). The hazard ratio for mortality of patients with more than or equal to 5 CTCs compared with those with less than 5 CTCs was 3.95 (1.20-13.0, P = .0245).

CONCLUSIONS

The presence of more than or equal to 5 CTCs in patients with metMTC is associated with worse OS. Larger cohorts are required to validate the prognostic value of CTC enumeration.

Reduction in membranous immunohistochemical staining for the intracellular domain of epithelial cell adhesion molecule correlates with poor patient outcome in primary colorectal adenocarcinoma

BACKGROUND

Epithelial cell adhesion molecule (epcam) is a multifunctional transmembrane glycoprotein expressed on both normal epithelium and epithelial neoplasms such as gastric, breast, and renal carcinomas. Recent studies have proposed that the proteolytic cleavage of the intracellular domain of epcam (epcam-icd) can trigger signalling cascades leading to aggressive tumour behavior. The expression profile of epcam-icd has not been elucidated for primary colorectal carcinoma. In the present study, we examined epcam-icd immunohistochemical staining in a large cohort of patients with primary colorectal adenocarcinoma and assessed its performance as a potential prognostic marker.

METHODS

Immunohistochemical staining for epcam-icd was assessed on tissue microarrays consisting of 137 primary colorectal adenocarcinoma samples. Intensity of staining for each core was scored by 3 independent pathologists. The membranous epcam-icd staining score was calculated as a weighted average from 3 core samples per tumour. Univariate analysis of the average scores and clinical outcome measures was performed.

RESULTS

The level of membranous epcam-icd staining was positively associated with well-differentiated tumours (p = 0.01); low preoperative carcinoembryonic antigen (p = 0.001); and several measures of survival, including 2-year (p = 0.02) and 5-year survival (p = 0.05), and length of time post-diagnosis (p = 0.03). A number of other variables-including stage, grade, and lymph node status-showed correlations with epcam staining and markers of poor outcome, but did not reach statistical significance.

CONCLUSIONS

Low membranous epcam-icd staining might be a useful marker to identify tumours with aggressive clinical behavior and potential poor prognosis and might help to select candidates who could potentially benefit from treatment targeting epcam.

Dynamic EpCAM expression on circulating and disseminating tumor cells: causes and consequences

Formation of metastasis is the most important and lethal step in cancer progression. Circulating and disseminated cancer cells (CTCs/DTCs) in blood and bone marrow are considered as potential metastases-inducing cells. Their detection and characterization has, therefore, become a field of major interest in translational and clinical research in oncology. The main strategy to detect these cells relies thus far on the epithelial characteristics of carcinoma cells and epithelial cell adhesion molecule (EpCAM) represents the most commonly used epithelial marker to capture CTCs/DTCs. Recent data, however, demonstrated a dynamic expression of EpCAM associated with a loss during epithelial-to-mesenchymal transition. The present review summarizes the potential mechanisms and reasons for a dynamic expression of EpCAM.

Coexpression of EpCAM, CD44 variant isoforms and claudin-7 in anaplastic thyroid carcinoma

Background

Anaplastic thyroid cancer is considered to be one of the most aggressive human malignancies, and the mean survival time after diagnosis is approximately six months, regardless of treatments. This study aimed to examine how EpCAM and its related molecules are involved in the characteristics of anaplastic thyroid carcinoma.

Methodology/Principal Findings

Two differentiated thyroid cancer cell lines (TPC-1 and FTC-133), and two anaplastic thyroid cancer cell lines (FRO, ACT-1) were analyzed for expression of CD44 standard isoform (CD44s), CD44 variant isoforms, and EpCAM, and human aldehyde dehydrogenase-1 (ALDH1) enzymatic activity using flow cytometry. CD44s expression was higher in TPC-1 and FTC-133 than in the FRO and ACT-1, whereas ALDH1 activities were higher in FRO and ACT-1 than in TPC-1 and FTC-133. An inverse correlation between CD44s expression and ALDH1 activity was observed in all thyroid cancer cell lines. As for the expressions of CD44 variant isoforms, ACT-1 showed higher and FRO showed moderate CD44v6 expressions, whereas either TPC-1 or FTC-133 showed negative CD44v6 expression. EpCAM expressions in FRO and ACT-1 were higher than those in TPC-1 and FTC-133, and EpCAM expressions inversely correlated with those of CD44s. A positive correlation was observed between EpCAM expression and ALDH1 activity in thyroid cancer cell lines. In the RT-PCR analysis, the expression levels of EpCAM, caludin-7 and ALDH1 in FRO and ATC-1 cells were significantly higher than those in TPC-1 and FTC-133 cells. In clinical specimens of thyroid cancers, nuclear expression of EpCAM and high expression of CD44v6 were detected significantly more frequently in anaplastic carcinomas.

Conclusions/Significance

Our study suggests the possibility that EpCAM, together with CD44v6 and claudin-7 as well as ALDH1, may be involved in the development of the aggressive phenotype of anaplastic thyroid carcinoma. Our findings may suggest a novel therapeutic strategy for treatment of anaplastic thyroid carcinoma.

Prognostic biomarkers in thyroid cancer

Thyroid carcinomas represent a challenging problem from the prognostic standpoint. Despite an overall good prognosis of the most frequent endocrine malignancy, 10-15 % of papillary thyroid carcinomas (PTCs) turn refractory to radioactive iodine therapy. The increased incidence of thyroid cancer has led to the search for solid prognostic biomarkers that predict the behaviour of these tumours. Clinical and histopathological prognostic factors remain the only safe elements to be used for diagnosis and prognosis of patients with thyroid tumours. Despite the huge amount of genetic information of thyroid tumours, very few new markers revealed diagnostic or prognostic value per se. BRAF mutation can have some value if associated to other clinico-pathological parameters, or in the particular setting of iodine refractory tumours. Others can prove interesting in the future as predictive biomarkers of therapeutic response, but more studies are needed to confirm these potential biomarkers.

Immunohistochemical analysis based Ep-ICD subcellular localization index (ESLI) is a novel marker for metastatic papillary thyroid microcarcinoma

Background

Thyroid cancer is among the fastest growing malignancies; almost fifty-percent of these rapidly increasing incidence tumors are less than or equal to 1cm in size, termed papillary thyroid microcarcinoma (PTMC). The management of PTMC remains a controversy due to differing natural history of these patients. Epithelial cell adhesion molecule (EpCAM) is comprised of an extracellular domain (EpEx), a single transmembrane domain and an intracellular domain (Ep-ICD). Our group reported nuclear Ep-ICD correlated with poor prognosis in thyroid cancer (Ralhan et al., BMC Cancer 2010,10:331). Here in, we hypothesized nuclear and cytoplasmic accumulation of Ep-ICD and loss of membranous EpEx may aid in distinguishing metastatic from non-metastatic PTMC, which is an important current clinical challenge. To test our hypothesis, Ep-ICD and EpEx expression levels were analyzed in PTMC and the staining was correlated with metastatic potential of these carcinomas.

Methods

Thirty-six PTMC patients (tumor size 0.5 - 1cm; metastatic 8 cases and non-metastatic 28 cases) who underwent total thyroidectomy were selected. The metastatic group consisted of patients who developed lymph node or distant metastasis at diagnosis or during follow up. The patients’ tissues were stained for Ep-ICD and EpEx using domain specific antibodies by immunohistochemistry and evaluated.

Results

PTMC patients with metastasis had higher scores for nuclear and cytoplasmic Ep-ICD immunostaining than the patients without metastasis (1.96 ± 0.86 vs. 1.22 ± 0.45; p = 0.007 and 5.37 ± 0.33 vs. 4.72 ± 1.07; p = 0.016, respectively). Concomitantly, the former had lower scores for membrane EpEx than the non-metastatic group (4.64 ± 1.08 vs. 5.64 ± 1.51; p = 0.026). An index of aggressiveness, Ep-ICD subcellular localization index (ESLI), was defined as sum of the IHC scores for accumulation of nuclear and cytoplasmic Ep-ICD and loss of membranous EpEx; ESLI = [Ep − ICD_nuc + Ep − ICD_cyt + loss of membranous EpEx]. Notably, ESLI correlated significantly with lymph node metastasis in PTMC (p = 0.008).

Conclusion

Nuclear and cytoplasmic Ep-ICD expression and loss of membranous EpEx were found to correlate positively with metastasis in PTMC patients. In addition, ESLI had the potential to identify metastatic behavior in PTMC which could serve as a valuable tool for solving a current dilemma in clinical practice.