Elevated serum sialyl Lewis X-i antigen levels in non-small cell lung cancer with lung metastasis

Identification of FUT7 hypomethylation as the blood biomarker in the prediction of early-stage lung cancer

Early detection of lung cancer (LC) is vital for reducing LC-related mortality. However, noninvasive diagnostic tools remain a great challenge. We aim to identify blood-based biomarkers for the early detection of LC. Here, LC-associated hypomethylation in alpha-1,3-fucosyltransferase VII (FUT7) is identified via the Illumina 850K array in a discovery study and validated by mass spectrometry in two independent case-control studies with blood samples from 1720 LC patients (86.8% LC at stage I, blood is collected before surgery and treatment) and 3143 healthy controls. Compared to the controls, blood-based FUT7 hypomethylation is identified in LC patients at stage I, and even in LC patients with malignant nodules ≤ 1 cm and in patients with adenocarcinoma in situ. Gender plays a role in the LC-associated FUT7 hypomethylation in blood, which is more significant in males than in females. We also reveal that FUT7 hypomethylation in LC could be enhanced by the advanced stage of cancer, involvement of lymph nodes, and larger tumor size. Based on a large sample size and semi-quantitative methods, our study reveals a strong association between blood-based FUT7 hypomethylation and LC, suggesting that methylation signatures in blood may be a group of potential biomarkers for detection of early-stage LC.

Metastasis of cholangiocarcinoma is promoted by extended high-mannose glycans

Membrane-bound oligosaccharides form the interfacial boundary between the cell and its environment, mediating processes such as adhesion and signaling. These structures can undergo dynamic changes in composition and expression based on cell type, external stimuli, and genetic factors. Glycosylation, therefore, is a promising target of therapeutic interventions for presently incurable forms of advanced cancer. Here, we show that cholangiocarcinoma metastasis is characterized by down-regulation of the Golgi α-mannosidase I coding gene MAN1A1, leading to elevation of extended high-mannose glycans with terminating α-1,2-mannose residues. Subsequent reshaping of the glycome by inhibiting α-mannosidase I resulted in significantly higher migratory and invasive capabilities while masking cell surface mannosylation suppressed metastasis-related phenotypes. Exclusive elucidation of differentially expressed membrane glycoproteins and molecular modeling suggested that extended high-mannose glycosylation at the helical domain of transferrin receptor protein 1 promotes conformational changes that improve noncovalent interaction energies and lead to enhancement of cell migration in metastatic cholangiocarcinoma. The results provide support that α-1,2-mannosylated N-glycans present on cancer cell membrane proteins may serve as therapeutic targets for preventing metastasis.

Carcinoembryonic antigen is a sialyl Lewis x/a carrier and an E‑selectin ligand in non‑small cell lung cancer

The formation of distant metastasis resulting from vascular dissemination is one of the leading causes of mortality in non-small cell lung cancer (NSCLC). This metastatic dissemination initiates with the adhesion of circulating cancer cells to the endothelium. The minimal requirement for the binding of leukocytes to endothelial E-selectins and subsequent transmigration is the epitope of the fucosylated glycan, sialyl Lewis x (sLe^x), attached to specific cell surface glycoproteins. sLe^x and its isomer sialyl Lewis a (sLe^a) have been described in NSCLC, but their functional role in cancer cell adhesion to endothelium is still poorly understood. In this study, it was hypothesised that, similarly to leukocytes, sLe glycans play a role in NSCLC cell adhesion to E-selectins. To assess this, paired tumour and normal lung tissue samples from 18 NSCLC patients were analyzed. Immunoblotting and immunohisto-chemistry assays demonstrated that tumour tissues exhibited significantly stronger reactivity with anti-sLe^x/sLe^a antibody and E-selectin chimera than normal tissues (2.2- and 1.8-fold higher, respectively), as well as a higher immunoreactive score. High sLe^x/sLe^a expression was associated with bone metastasis. The overall α1,3-fucosyltransferase (FUT) activity was increased in tumour tissues, along with the mRNA levels of FUT3, FUT6 and FUT7, whereas FUT4 mRNA expression was decreased. The expression of E-selectin ligands exhibited a weak but significant correlation with the FUT3/FUT4 and FUT7/FUT4 ratios. Additionally, carcinoembryonic antigen (CEA) was identified in only 8 of the 18 tumour tissues; CEA-positive tissues exhibited significantly increased sLe^x/sLe^a expression. Tumour tissue areas expressing CEA also expressed sLe^x/sLe^a and showed reactivity to E-selectin. Blot rolling assays further demonstrated that CEA immunoprecipitates exhibited sustained adhesive interactions with E-selectin-expressing cells, suggesting CEA acts as a functional protein scaffold for E-selectin ligands in NSCLC. In conclusion, this work provides the first demonstration that sLe^x/sLe^a are increased in primary NSCLC due to increased α1,3-FUT activity. sLe^x/sLe^a is carried by CEA and confers the ability for NSCLC cells to bind E-selectins, and is potentially associated with bone metastasis. This study contributes to identifying potential future diagnostic/prognostic biomarkers and therapeutic targets for lung cancer.

Sialyl Lewis X as a predictor of skip N2 metastasis in clinical stage IA non-small cell lung cancer

Background

Radical segmentectomy has been performed for small-sized non-small cell lung cancer (NSCLC). However, underestimation of mediastinal lymph node metastasis in the absence of hilar or interlobar metastasis (skip N2) affects surgical strategy. Our aim was to investigate preoperative and intraoperative predictors of skip N2 in clinical stage (c-stage) IA NSCLC.

Methods

From 1998 to 2011, 279 patients (155 men and 124 women) with c-stage IA NSCLC (230 pN0, 17 pN1, 12 skip N2, 20 non-skip N2) underwent systematic lobectomy (R0 resection) at our institute. We compared preoperative serum concentrations of carcinoembryonic antigen, cytokeratin 19 fragment, sialyl Lewis X (SLX), and pre- and intraoperative clinicopathological features of pN0 and skip N2 patients. Receiver operator characteristic (ROC) curve analysis was performed to distinguish between the two patient groups.

Results

The 5-year survival rate of skip N2 patients was 78.6%, higher than that of non-skip N2 patients (44.9%), and not significantly different than that of pN0 (86.7%) or pN1 patients (82.4%). The mean serum SLX concentration in skip N2 patients (28.0 U/ml) was elevated compared to that in pN0 patients (22.9 U/ml). In ROC analysis of SLX, the area under the curve was 0.710, and the optimal cut-off value was 21.4 U/ml (sensitivity, 91.7%; specificity, 51.7%). In multivariate analysis, SLX was an independent predictor of skip N2 in patients with c-stage IA NSCLC (odds ratio, 9.43; p = 0.006).

Conclusions

Skip N2 metastasis is common in patients with c-stage IA NSCLC with high serum SLX, and lobectomy with complete dissection of hilar and mediastinal lymph nodes should remain the standard surgical procedure for these cases.

Preoperative serum value of sialyl Lewis X predicts pathological nodal extension and survival in patients with surgically treated small cell lung cancer

BACKGROUND AND OBJECTIVES

We investigated various tumor markers in patients with surgically treated small cell lung cancer (SCLC) to identify the markers closely correlated to pathological staging and to predict survival by retrospective analyses.

METHODS

Reviewing database records between 1990 and 2007 revealed 36 patients with SCLC, that were grouped according to clinical and pathological stages. Receiver operating characteristic (ROC) curves were calculated for serum levels of various tumor makers to predict the pathological stage. The cut-off value was calculated from the ROC curve of the significant marker. Survival in patient groups divided by the new cut-off value was calculated.

RESULTS

Serum levels of various tumor makers were not significantly different between the pathological stage groups, except for serum sialyl Lewis X (SLX). ROC curve of SLX was significantly correlated to pathological stages (P = 0.0136). The calculated SLX cut-off value was 25.1 U/ml, with 80% sensitivity and 70% specificity. Five-year survival of patients selected by this new cut-off was 82.5%, whereas that with the standard cut-off (38.0 U/ml) was 55.9%.

CONCLUSIONS

Serum SLX values were associated with pathological stage and survival after surgery in SCLC patients.

Expression of CEACAM1 in adenocarcinoma of the lung: a factor of independent prognostic significance

PURPOSE

To evaluate the prognostic relevance of CEACAM1 and sialyl Lewis X expression in adenocarcinomas of the lung.

PATIENTS AND METHODS

Paraffin wax sections of 93 patients with adenocarcinomas of the lung who underwent surgery between 1990 and 1995 were immunohistochemically investigated using monoclonal anti-CEACAM1 and sialyl Lewis X antibodies. The clinical course of all patients was followed up for a minimum of 5 years.

RESULTS

Sixty-one tumors were classified as CEACAM1-positive, and 32 were classified as CEACAM1-negative. Patients with CEACAM1-positive tumors had a significantly poorer overall (P =.00025) and relapse-free (P =.00029) survival than those with CEACAM1-negative tumors. Only three patients did not express the sialyl Lewis X glycotope, whereas 90 tumors (97%) were sialyl Lewis X-positive. In multivariate Cox regression analysis, next to tumor stage and sex, only the expression of CEACAM1 was a significant independent prognostic factor for survival.

CONCLUSION

Expression of CEACAM1 was an independent prognostic factor in our patient population and can be used to stratify patients with adenocarcinomas of the lung into low-risk and high-risk groups. In contrast, the expression of sialyl Lewis X was of no prognostic relevance because it was expressed in 97% of all investigated tumors, and most likely has no influence on the function of CEACAM1 in this tumor entity.

ABH and Lewis histo-blood group antigens in cancer

Antigens of the ABH and Lewis histo-blood group family can be found on many normal cells, mainly of epithelial type. In carcinomas, altered expression of the various carbohydrate epitopes of this family occur, and are often strongly associated with either a good or bad prognosis. A review of the available data on these tumor-associated markers, their biosynthesis and their prognostic value is proposed here. For a long time it has been unclear whether their presence could affect the behavior of carcinoma cells. Recent data, however, indicate that they play biological roles in the course of tumor progression. The presence of sialyl-Le(a) or sialyl-Le(x), which are ligands for selectins, promotes the metastatic process by facilitating interaction with the endothelium of distant organs. The loss of A and B antigens increases cellular motility, while the presence of H epitopes increases resistance to apoptosis by mechanisms that remain to be defined. The Le(y) antigen has procoagulant and angiogenic activities. All these observations are used to present a model that may account for the described associations between the presence or loss of these markers and the outcome of disease. Finally, their potential clinical applications as tumor-associated markers or as targets of immunotherapy are reviewed.