Immunohistochemical expression of the sialyl Lewis x antigen on gastric cancer cells correlates with the presence of liver metastasis

PSGL-1 decorated with sialyl Lewisa/x promotes high affinity binding of myeloma cells to P-selectin but is dispensable for E-selectin engagement

Dissemination of multiple myeloma into the bone marrow proceeds through sequential steps mediated by a variety of adhesion molecules and chemokines that eventually results in the extravasation of malignant plasma cells into this protective niche. Selectins are a class of C-type lectins that recognize carbohydrate structures exposed on blood borne cells and participate in the first step of the extravasation cascade, serving as brakes to slow down circulating cells enabling them to establish firm adhesion onto the endothelium. Myeloma cells enriched for the expression of selectin ligands present an aggressive disease in vivo that is refractory to bortezomib treatment and can be reverted by small molecules targeting E-selectin. In this study, we have defined the molecular determinants of the selectin ligands expressed on myeloma cells. We show that PSGL-1 is the main protein carrier of sialyl Lewisa/x-related structures in myeloma. PSGL-1 decorated with sialyl Lewisa/x is essential for P-selectin binding but dispensable for E-selectin binding. Moreover, sialylation is required for E-selectin engagement whereas high affinity binding to P-selectin occurs even in the absence of sialic acid. This study provides further knowledge on the biology of selectin ligands in myeloma, opening the way to their clinical application as diagnostic tools and therapeutic targets.

Pathophysiological roles and applications of glycosphingolipids in the diagnosis and treatment of cancer diseases

Glycosphingolipids (GSLs) are major amphiphilic glycolipids present on the surface of living cell membranes. They have important biological functions, including maintaining plasma membrane stability, regulating signal transduction, and mediating cell recognition and adhesion. Specific GSLs and related enzymes are abnormally expressed in many cancer diseases and affect the malignant characteristics of tumors. The regulatory roles of GSLs in signaling pathways suggest that they are involved in tumor pathogenesis. GSLs have therefore been widely studied as diagnostic markers of cancer diseases and important targets of immunotherapy. This review describes the tumor-related biological functions of GSLs and systematically introduces recent progress in using diverse GSLs and related enzymes to diagnose and treat tumor diseases. Development of drugs and biomarkers for personalized cancer therapy based on GSL structure is also discussed. These advances, combined with recent progress in the preparation of GSLs derivatives through synthetic biology technologies, suggest a strong future for the use of customized GSL libraries in treating human diseases.

Knockdown of α2,3-Sialyltransferases Impairs Pancreatic Cancer Cell Migration, Invasion and E-selectin-Dependent Adhesion

Aberrant sialylation is frequently found in pancreatic ductal adenocarcinoma (PDA). α2,3-Sialyltransferases (α2,3-STs) ST3GAL3 and ST3GAL4 are overexpressed in PDA tissues and are responsible for increased biosynthesis of sialyl-Lewis (sLe) antigens, which play an important role in metastasis. This study addresses the effect of α2,3-STs knockdown on the migratory and invasive phenotype of PDA cells, and on E-selectin-dependent adhesion. Characterization of the cell sialome, the α2,3-STs and fucosyltransferases involved in the biosynthesis of sLe antigens, using a panel of human PDA cells showed differences in the levels of sialylated determinants and α2,3-STs expression, reflecting their phenotypic heterogeneity. Knockdown of ST3GAL3 and ST3GAL4 in BxPC-3 and Capan-1 cells, which expressed moderate to high levels of sLe antigens and α2,3-STs, led to a significant reduction in sLe^x and in most cases in sLe^a, with slight increases in the α2,6-sialic acid content. Moreover, ST3GAL3 and ST3GAL4 downregulation resulted in a significant decrease in cell migration and invasion. Binding and rolling to E-selectin, which represent key steps in metastasis, were also markedly impaired in the α2,3-STs knockdown cells. Our results indicate that inhibition of ST3GAL3 and ST3GAL4 may be a novel strategy to block PDA metastasis, which is one of the reasons for its dismal prognosis.

Targeted Approaches to Inhibit Sialylation of Multiple Myeloma in the Bone Marrow Microenvironment

Aberrant glycosylation modulates different aspects of tumor biology, and it has long been recognized as a hallmark of cancer. Among the different forms of glycosylation, sialylation, the addition of sialic acid to underlying oligosaccharides, is often dysregulated in cancer. Increased expression of sialylated glycans has been observed in many types of cancer, including multiple myeloma, and often correlates with aggressive metastatic behavior. Myeloma, a cancer of plasma cells, develops in the bone marrow, and colonizes multiple sites of the skeleton including the skull. In myeloma, the bone marrow represents an essential niche where the malignant cells are nurtured by the microenvironment and protected from chemotherapy. Here, we discuss the role of hypersialylation in the metastatic process focusing on multiple myeloma. In particular, we examine how increased sialylation modulates homing of malignant plasma cells into the bone marrow by regulating the activity of molecules important in bone marrow cellular trafficking including selectins and integrins. We also propose that inhibiting sialylation may represent a new therapeutic strategy to overcome bone marrow-mediated chemotherapy resistance and describe different targeted approaches to specifically deliver sialylation inhibitors to the bone marrow microenvironment.

Staining of E-selectin ligands on paraffin-embedded sections of tumor tissue

Background

The E-selectin ligands expressed by cancer cells mediate adhesion of circulating cancer cells to endothelial cells, as well as within tissue microenvironments important for tumor progression and metastasis. The identification of E-selectin ligands within cancer tissue could yield new biomarkers for patient stratification and aid in identifying novel therapeutic targets. The determinants of selectin ligands consist of sialylated tetrasaccharides, the sialyl Lewis X and A (sLe^X and sLe^A), displayed on protein or lipid scaffolds. Standardized procedures for immunohistochemistry make use of the antibodies against sLe^X and/or sLe^A. However, antibody binding does not define E-selectin binding activity.

Methods

In this study, we developed an immunohistochemical staining technique, using E-selectin-human Ig Fc chimera (E-Ig) to characterize the expression and localization of E-selectin binding sites on paraffin-embedded sections of different cancer tissue.

Results

E-Ig successfully stained cancer cells with high specificity. The E-Ig staining show high reactivity scores in colon and lung adenocarcinoma and moderate reactivity in triple negative breast cancer. Compared with reactivity of antibody against sLe^X/A, the E-Ig staining presented higher specificity to cancer tissue with better defined borders and less background.

Conclusions

The E-Ig staining technique allows the qualitative and semi-quantitative analysis of E-selectin binding activity on cancer cells. The development of accurate techniques for detection of selectin ligands may contribute to better diagnostic and better understanding of the molecular basis of tumor progression and metastasis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4410-x) contains supplementary material, which is available to authorized users.

Clinicopathological and prognostic significance of sialyl Lewis X overexpression in patients with cancer: a meta-analysis

Many studies have shown that sialyl Lewis X (sLe^X) is related to cancer prognosis and clinicopathology, but failed to provide conclusive results. We conducted the present meta-analysis to identify the association between sLe^X overexpression and cancer prognosis. We searched studies in PubMed and Embase databases. Relative risk or hazard ratio with 95% confidence intervals were estimated with the Mantel–Haenszel random-effect method and 29 studies were included. Our meta-analysis showed that sLe^X overexpression is significantly related to lymphatic invasion, venous invasion, T stage, N stage, M stage, tumor stage, recurrence, and overall survival. In subgroup analysis, we found that cancer type and ethnicity might be two major contributing factors to the possible presence of heterogeneity among the studies. In conclusion, sLe^X overexpression is associated with tumor metastasis, recurrence, and overall survival in cancer patients, it plays an important role in cancer prognosis.

Glycomic analysis of gastric carcinoma cells discloses glycans as modulators of RON receptor tyrosine kinase activation in cancer

BACKGROUND

Terminal α2-3 and α2-6 sialylation of glycans precludes further chain elongation, leading to the biosynthesis of cancer relevant epitopes such as sialyl-Lewis X (SLe(X)). SLe(X) overexpression is associated with tumor aggressive phenotype and patients' poor prognosis.

METHODS

MKN45 gastric carcinoma cells transfected with the sialyltransferase ST3GAL4 were established as a model overexpressing sialylated terminal glycans. We have evaluated at the structural level the glycome and the sialoproteome of this gastric cancer cell line applying liquid chromatography and mass spectrometry. We further validated an identified target expression by proximity ligation assay in gastric tumors.

RESULTS

Our results showed that ST3GAL4 overexpression leads to several glycosylation alterations, including reduced O-glycan extension and decreased bisected and increased branched N-glycans. A shift from α2-6 towards α2-3 linked sialylated N-glycans was also observed. Sialoproteomic analysis further identified 47 proteins with significantly increased sialylated N-glycans. These included integrins, insulin receptor, carcinoembryonic antigens and RON receptor tyrosine kinase, which are proteins known to be key players in malignancy. Further analysis of RON confirmed its modification with SLe(X) and the concomitant activation. SLe(X) and RON co-expression was validated in gastric tumors.

CONCLUSION

The overexpression of ST3GAL4 interferes with the overall glycophenotype of cancer cells affecting a multitude of key proteins involved in malignancy. Aberrant glycosylation of the RON receptor was shown as an alternative mechanism of oncogenic activation.

GENERAL SIGNIFICANCE

This study provides novel targets and points to an integrative tumor glycomic/proteomic-profiling for gastric cancer patients' stratification. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Altered tumor-cell glycosylation promotes metastasis

Malignant transformation of cells is associated with aberrant glycosylation presented on the cell-surface. Commonly observed changes in glycan structures during malignancy encompass aberrant expression and glycosylation of mucins; abnormal branching of N-glycans; and increased presence of sialic acid on proteins and glycolipids. Accumulating evidence supports the notion that the presence of certain glycan structures correlates with cancer progression by affecting tumor-cell invasiveness, ability to disseminate through the blood circulation and to metastasize in distant organs. During metastasis tumor-cell-derived glycans enable binding to cells in their microenvironment including endothelium and blood constituents through glycan-binding receptors – lectins. In this review, we will discuss current concepts how tumor-cell-derived glycans contribute to metastasis with the focus on three types of lectins: siglecs, galectins, and selectins. Siglecs are present on virtually all hematopoietic cells and usually negatively regulate immune responses. Galectins are mostly expressed by tumor cells and support tumor-cell survival. Selectins are vascular adhesion receptors that promote tumor-cell dissemination. All lectins facilitate interactions within the tumor microenvironment and thereby promote cancer progression. The identification of mechanisms how tumor glycans contribute to metastasis may help to improve diagnosis, prognosis, and aid to develop clinical strategies to prevent metastasis.

Metastatic growth progression caused by PSGL-1-mediated recruitment of monocytes to metastatic sites

Tumor cell-derived selectin ligands mediate contact to the endothelium, platelets, and leukocytes through binding to selectins that facilitates metastasis. Here, we describe the mechanism of how endogenous (non-tumor derived) selectin ligands contribute to metastasis using α(1,3)fucosyltransferase 7 (Fuc-TVII(-/-))-deficient mice. Experimental metastasis of MC-38GFP and Lewis lung (3LL) carcinoma cells was attenuated in Fuc-TVII(-/-) mice, which express minimal amount of selectin ligands. We show that metastasis is dependent on selectin ligands carried on hematopoietic cells. P-selectin glycoprotein ligand-1 (PSGL-1) was identified as the major ligand facilitating monocyte accumulation at metastatic sites. Reduced recruitment of monocytes to metastasizing tumor cells in Fuc-TVII(-/-) mice correlated with attenuated metastasis. Adoptive transfer of Fuc-T7(+) monocytes rescued metastasis in Fuc-TVII(-/-) mice, indicating that selectin ligand-dependent recruitment of monocytes is required for cancer progression. Cytokine analysis in metastatic lungs revealed high expression of CCL2 in C57BL/6 mice that was significantly lower in Fuc-TVII(-/-) mice. The absence of monocyte recruitment in Fuc-TVII(-/-) mice correlated with increased apoptosis of tumor cells. Thus, the recruitment of monocytes to metastasizing tumor cells is facilitated by endogenous selectin ligands on monocytes that enable efficient tumor cell survival, extravasation, and metastasis.

Regulation of the metastatic cell phenotype by sialylated glycans

Tumor cells exhibit striking changes in cell surface glycosylation as a consequence of dysregulated glycosyltransferases and glycosidases. In particular, an increase in the expression of certain sialylated glycans is a prominent feature of many transformed cells. Altered sialylation has long been associated with metastatic cell behaviors including invasion and enhanced cell survival; however, there is limited information regarding the molecular details of how distinct sialylated structures or sialylated carrier proteins regulate cell signaling to control responses such as adhesion/migration or resistance to specific apoptotic pathways. The goal of this review is to highlight selected examples of sialylated glycans for which there is some knowledge of molecular mechanisms linking aberrant sialylation to critical processes involved in metastasis.

Expression of ST3GAL4 leads to SLe(x) expression and induces c-Met activation and an invasive phenotype in gastric carcinoma cells

Sialyl-Lewis X (SLe(x)) is a sialylated glycan antigen expressed on the cell surface during malignant cell transformation and is associated with cancer progression and poor prognosis. The increased expression of sialylated glycans is associated with alterations in the expression of sialyltransferases (STs). In this study we determined the capacity of ST3GAL3 and ST3GAL4 sialyltransferases to synthesize the SLe(x) antigen in MKN45 gastric carcinoma cells and evaluated the effect of SLe(x) overexpression in cancer cell behavior both in vitro and in vivo using the chicken chorioallantoic membrane (CAM) model. The activation of tyrosine kinase receptors and their downstream molecular targets was also addressed. Our results showed that the expression of ST3GAL4 in MKN45 gastric cancer cells leads to the synthesis of SLe(x) antigens and to an increased invasive phenotype both in vitro and in the in vivo CAM model. Analysis of phosphorylation of tyrosine kinase receptors showed a specific increase in c-Met activation. The characterization of downstream molecular targets of c-Met activation, involved in the invasive phenotype, revealed increased phosphorylation of FAK and Src proteins and activation of Cdc42, Rac1 and RhoA GTPases. Inhibition of c-Met and Src activation abolished the observed increased cell invasive phenotype. In conclusion, the expression of ST3GAL4 leads to SLe(x) antigen expression in gastric cancer cells which in turn induces an increased invasive phenotype through the activation of c-Met, in association with Src, FAK and Cdc42, Rac1 and RhoA GTPases activation.

Regulation of glycosyltransferases and Lewis antigens expression by IL-1β and IL-6 in human gastric cancer cells

Inflammation of stomach mucosa has been postulated as initiator of gastric carcinogenesis and the presence of pro-inflammatory cytokines can regulate specific genes involved in this process. The cellular expression pattern of glycosyltransferases and Lewis antigens detected in the normal mucosa changed during the neoplassic transformation. The aim of this work was to determine the regulation of specific fucosyltransferases and sialyltransferases by IL-1β and IL-6 pro-inflammatory cytokines in MKN45 gastric cancer cells. IL-1β induced significant increases in the mRNA levels of FUT1, FUT2 and FUT4, and decreases of FUT3 and FUT5. In IL-6 treatments, enhanced FUT1 and lower FUT3 and FUT5 mRNA expression were detected. No substantial changes were observed in the levels of ST3GalIII and ST3GalIV. The activation of FUT1, FUT2 and FUT4 by IL-1β is through the NF-κB pathway and the down-regulation of FUT3 and FUT5 by IL-6 is through the gp130/STAT-3 pathway, since they are inhibited specifically by panepoxydone and AG490, respectively. The levels of Lewis antigens after IL-1β or IL-6 stimulation decreased for sialyl-Lewis x, and no significant differences were found in the rest of the Lewis antigens analyzed, as it was also observed in subcutaneous mice tumors from MKN45 cells treated with IL-1β or IL-6. In addition, in 61 human intestinal-type gastric tumors, sialyl-Lewis x was highly detected in samples from patients that developed metastasis. These results indicate that the expression of the fucosyltransferases involved in the synthesis of Lewis antigens in gastric cancer cells can be specifically modulated by IL-1β and IL-6 inflammatory cytokines.

Alterations in glycosylation as biomarkers for cancer detection

Glycoconjugates constitute a major class of biomolecules which include glycoproteins, glycosphingolipids and proteoglycans. Glycans are involved in several physiological and pathological conditions, such as host-pathogen interactions, cell differentiation, migration, tumour invasion and metastisation, cell trafficking and signalling. Cancer is associated with glycosylation alterations in glycoproteins and glycolipids. This review describes various aspects of protein glycosylation with the focus on alterations associated with human cancer. The application of these glycosylation modifications as biomarkers for cancer detection in tumour tissues and serological assays is summarised.

Heparin as an inhibitor of cancer progression

Heparin is frequently used in the treatment of cancer-associated thromboembolism. Accumulating clinical evidence indicates that cancer patients treated with unfractionated and low-molecular weight heparin (LMWH) survive longer than patients treated by other anticoagulants, especially patients in the early stage of the disease. Experimental analysis from a number of animal models constantly provides evidence for the ability of heparin to attenuate metastasis. The non-anticoagulant activity of heparin on metastasis includes the ability to inhibit cell-cell-interaction through blocking of P- and L-selectin, to inhibit extracellular matrix protease heparanase, and to inhibit angiogenesis. This chapter summarizes current experimental evidence on the biology of heparin during cancer progression, with the focus on potential mechanism of heparin antimetastatic activity.

Epithelial repair is inhibited by an alpha(1,6)-fucose binding lectin

The effective repair of damage to the airway epithelium is essential to maintain the ability to exclude airborne particulates and protect against potential pathogens. Carbohydrates on the cell surface have an important role in cell-cell and cell substrate interactions. Using a model of repair with airway epithelial-derived cells of the 16HBE 14o(-) cell line, we have examined the effect of the Aleuria aurantia lectin (AAL), which binds very selectively to alpha(1,6)-linked fucose residues. Addition of unconjugated or FITC-labeled AAL reduced the rate of epithelial repair to approximately one-third of control values as measured by image analysis while cell viability was maintained. Pulse labeling with AAL-FITC for 30 min followed by incubation in AAL-free medium caused similar inhibition of repair but could be reversed by addition of fucose up to 7 h after AAL removal. By confocal microscopy, AAL binding was found to be on the apical, but not basolateral, surfaces of cells, and internalization of the labeled lectin was seen. Preincubation of the lectin with fucose prevented this effect. Ulex europeaus I lectin, which is also fucose specific, resulted in similar binding to the cells and internalization, but it did not affect the speed of the repair process. We conclude that alpha(1,6)-fucose binding sites play an important role in epithelial repair. Better understanding of this process will provide a deeper insight into the crucial mechanisms of epithelial repair.

Disseminated cancer cells in the blood and expression of sialylated antigen in gastric cancer

BACKGROUND

In gastric cancer, disseminated cancer cells (DCC) can be detected in peripheral blood using bio-molecular techniques. It is known that patients having DCC exhibit a high occurrence of postoperative relapse in gastrointestinal cancer. However, more than half of gastric cancer patients having positive DCC do not show cancer relapse. Sialylated Lewis antigens are considered to be crucial molecules in the metastasis of disseminated cancer. The current study investigated whether combination analysis of DCC and sialylated Lewis antigen are useful in estimating the recurrence risk of gastric cancer.

PATIENTS AND METHODS

Subjects were 106 consecutive gastric cancer patients who underwent curative gastrectomy. DCC in the peripheral blood were detected using the carcinoembryonic antigen (CEA)-mRNA by RT-PCR method. Sialylated Lewis antigen expression (sLeA and sLeX) of the primary tumor was assessed immunohistochemically.

RESULTS

Of 106 gastric cancer patients, 43 (40%) were positive for DCC. Immunohistochemically, 53 (50%) and 49 (46%) patients were positive for sLeA and sLeX, respectively. The presence of DCC did not correlate with sLeA and sLeX expression in gastric cancer. Postoperative tumors were present in 19 patients (7 hematogenous and 12 non-hematogenous), 12 of which were positive for DCC. Six sLeA-positive patients (26%) with DCC and 13 sLeX-positive patients (57%) with DCC suffered from postoperative recurrence of gastric cancer. The p value of CEA-mRNA and sLeX combination analysis was more significant (p<0.01) than that of CEA-mRNA alone (p=0.02).

CONCLUSION

Analyzing both DCC and sLeX expression in gastric cancer may enable more accurate prediction of postoperative recurrence.

Binding of gastrointestinal tumor cells to endothelial E- and P-selectin adhesion receptors leads to transient down-regulation of sLeX ligands in vitro

BACKGROUND AND AIMS

The prognostic relevance of sialyl Lewis X (sLeX) expression in colorectal and gastric cancer and its relevance to the hematogenous phase of tumor invasion is controversial. This study was designed to evaluate sLeX expression during tumor cell-endothelial cell interaction in vitro.

METHODS

Adhesion and transendothelial penetration of MKN45, PaCa-2, WiDr, or Dan-G cells was analyzed by combined phase contrast-reflection interference contrast microscopy. In parallel, kinetics of membranous sLeX expression were examined fluorimetrically. To identify factor(s) which may be responsible for sLeX expression during tumor invasion tumor cells were treated with soluble immunomodulators, isolated endothelial plasma membranes, or E-selectin or P-selectin IgG fusion proteins. sLeX was then analyzed by flow cytometry.

RESULTS

Fluorometric quantification of sLeX demonstrated an inverse correlation between basal sLeX expression level and adhesion capacity of the tumor cells. Unexpectedly, sLeX was strongly down-regulated on tumor cell membranes in the course of heterophilic cell-cell contacts. The process occurred transiently, with a maximum effect 30-60 min after introducing tumor cells to the endothelial monolayer. Binding of tumor cells to immobilized E- and P-selectin IgG globulin chimeras was shown to be responsible for this phenomenon.

CONCLUSION

A transient loss of sLeX is necessary for gastrointestinal tumor cells to invade endothelial cells. Due to the transient nature of the decrease in sLeX the controversy about the prognostic relevance of sLeX expression in colorectal and gastric cancer may be rooted in the stage of tumor invasion at the time of sLeX measurement.

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.

The expression of sialyl Lewis X in canine and feline mammary gland tumors

The expression of sialyl Lewis X (sLe(x)) in 93 canine and 15 feline mammary gland tumors (MGT) obtained by surgical resection at Veterinary Medical Center, the University of Tokyo was examined by immunohistochemistry. Their clinicopathological features and prognosis were also reviewed. Approximately 60% of MGT tissues showed sLe(x) positive expressions, while all normal mammary gland tissues were negative. However, its expression was not correlated with clinicopathological features and prognosis significantly. This study suggests that sLe(x) may be a tumor-associated antigen in canine and feline MGTs.

Difference in prognostic value between sialyl Lewis(a) and sialyl Lewis(x) antigen levels in the preoperative serum of gastric cancer patients

Sialyl Lewis(a) (CA19-9) and sialyl Lewis(x) antigens (SLX) may play a role in tumor metastasis by serving as functional ligands in the cell adhesion system. The authors examined preoperative serum levels of CA19-9 and SLX in 218 patients who underwent resection for gastric cancer to determine their prognostic value. The patients were divided into two groups, termed the low and high antigen groups, based on a value selected as a diagnostic cutoff. Correlation between the antigen serum levels, various established clinicopathologic factors, and prognosis were studied by univariate and multivariate analysis. The disease-specific interval for high CA19-9 and SLX groups was significantly shorter than that of their respective low groups (p = 0.0024 and p < 0.0001, respectively). Patients with stage III/IV tumors who had high serum SLX levels had shorter disease-specific intervals than those with low serum levels (p = 0.0017). A Cox's regression analysis revealed a high serum SLX level as an independent factor for worse outcome. In addition, logistic regression analysis revealed that a high serum SLX level was an independent predictor for liver metastasis. In conclusion, an elevated preoperative serum SLX level was a predictor for poor outcome after resection for gastric cancer, whereas CA19-9 was not.

Increased expression of sialyl Lewis(x) antigen as a prognostic factor in patients with stage 0, I, and II gastric cancer

Immunohistochemically detected expression of sialyl Lewis(x) (Le(x)) antigen was analyzed in 101 stage 0-II gastric cancers to clarify its prognostic value after curative gastrectomy. Patients with a high-expression of sialyl Le(x) antigen within their tumors had shorter disease-specific intervals than those with negative- or low-expressing tumors (P<0.0001). This difference was noted particularly in stage I-B or II disease. Multivariate Cox's regression analysis revealed sialyl Le(x) antigen expression to be an independent predictor of disease-specific survival (Hazard ratio=9.10). In conclusion, the increased expression of sialyl Le(x) antigen may serve as a prognostic factor after curative surgery for stages 0-II gastric cancer.