Expression of tumor-associated 90K-antigen in human breast cancer: no correlation with prognosis and response to first-line therapy with tamoxifen

Galectin-3-binding protein: A multitask glycoprotein with innate immunity functions in viral and bacterial infections

Galectin-3-binding protein (Gal-3BP) is a ubiquitous and multifunctional secreted glycoprotein originally identified and mainly studied in the context of neoplastic transformation and cancer progression. However, Gal-3BP expression is induced in viral infection and by a multitude of molecules that either mimic or are characteristic for an ongoing inflammation and microbial infection, such as IFN-α, IFN-β, IFN-γ, TNF-α, poly(I:C), dsRNA, and dsDNA. Furthermore, Gal-3BP belongs to the scavenger receptor cysteine-rich (SRCR) domain-containing protein family, by virtue of its N-terminal SRCR domain. The SRCR domain is found in soluble or membrane-associated innate immunity-related proteins and is implicated in self-nonself discrimination. This review summarizes the current knowledge of structural features of Gal-3BP and its proposed intracellular and extracellular innate immunity functions with special emphasis on viral and bacterial infections.

Two E-selectin ligands, BST-2 and LGALS3BP, predict metastasis and poor survival of ER-negative breast cancer

Distant metastases account for the majority of cancer-related deaths in breast cancer. The rate and site of metastasis differ between estrogen receptor (ER)-negative and ER-positive tumours, and metastatic fate can be very diverse even within the ER-negative group. Characterisation of new pro-metastatic markers may help to identify patients with higher risk and improve their care accordingly. Selectin ligands aberrantly expressed by cancer cells promote metastasis by enabling interaction between circulating tumour cells and endothelial cells in distant organs. These ligands consist in carbohydrate molecules, such as sialyl-Lewis x antigen (sLex), borne by glycoproteins or glycolipids on the cancer cell surface. We have previously demonstrated that the molecular scaffold presenting sLex to selectins (e.g. glycolipid vs. glycoproteins) was crucial for these interactions to occur. Moreover, we reported that detection of sLex alone in breast carcinomas was only of limited prognostic value. However, since sLex was found to be carried by several glycoproteins in cancer cells, we hypothesized that the combination of the carbohydrate with its carriers could be more relevant than each marker independently. In this study, we addressed this question by analysing sLex expression together with two glycoproteins (BST-2 and LGALS3BP), shown to interact with E-selectin in a carbohydrate-dependent manner, in a cohort of 249 invasive breast cancers. We found both glycoproteins to be associated with distant metastasis risk and poorer survival. Importantly, concomitant high expression of BST-2 with sLex defined a sub-group of patients with ER-negative tumours displaying higher risks of liver and brain metastasis and a 3-fold decreased survival rate.

Biomarkers for malignant pleural mesothelioma: current status

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis, whose main etiology is exposure to asbestos fibers. The incidence of MPM is anticipated to increase worldwide during the first half of this century. For various reasons, MPM is difficult to diagnose and is notoriously refractory to most treatments. However, recently two active chemotherapy regimens have been demonstrated to significantly increase survival in patients with MPM, and several therapeutic agents and strategies are currently under evaluation.Researchers have actively sought MPM biomarkers for more than 20 years. Biomarkers would be helpful in managing three clinical aspects of MPM: early diagnosis, prognosis, and treatment outcome prediction. The aims of the present review are to summarize the published and recently presented data on MPM biomarkers and to identify the prospects for future translational research projects.Among the 'classical' diagnostic biomarkers measured in biological fluids, such as cytokeratins and cell surface antigens, none discriminate patients with MPM from those with other malignancies and nonmalignant diseases. Osteopontin, soluble mesothelin, and megakaryocyte potentiating factor (MPF) appear to be the most promising of the recent biomarkers, but are still subject to some limitations. Osteopontin lacks specificity for mesothelioma, while both soluble mesothelin and MPF lack sensitivity for detecting non-epithelial subtypes. Panels consisting of a small set of biomarkers do not improve the diagnostic yield, and results from molecular profiling are too preliminary to be brought into daily clinical practice. While a large number of biomarkers have been assessed in biological fluids and tumor tissue for their prognostic value, none have had a widespread impact on clinical practice. In contrast, data concerning predictive biomarkers are very limited, even though they are most interesting from the perspective of clinicians.Additional prospective studies, in large and independent samples of patients, with rigorous statistical methodology and standardized laboratory techniques are now warranted to validate and define the precise value of diagnostic and prognostic MPM biomarkers. Future research efforts should focus on biomarkers predictive of the efficacy and toxicity of standard chemotherapy. Translational research should be systematically incorporated into the design of clinical trials assessing new targeted agents in MPM.

Expression and immunogenicity of a tumor-associated antigen, 90K/Mac-2 binding protein, in lung carcinoma

BACKGROUND

The authors attempted to obtain shared proteins among lung carcinoma cells by column chromatographies. A glycoprotein with approximately 500 kDa isolated from QG56 cells showed an identical amino acid sequence to 90K/Mac-2 binding protein (M2BP). This protein has been reported to be highly expressed and to modulate the expression of surface molecules involved in immune responses on cultured cancer cells. Therefore, it would be beneficial for M2BP to be targeted in cancer immunotherapy.

METHODS

The authors analyzed the expression of M2BP in lung carcinoma cells and M2BP's immunogenicity as a tumor antigen. Eight cultured lung carcinoma cell lines and 28 tumor tissues from patients with lung carcinoma were examined for the expression of M2BP mRNA and protein. Sera from cancer patients (n = 23) and healthy donors (n = 19) were studied for their reactivity to M2BP peptides by enzyme-linked immunosorbent assay.

RESULTS

Seven of the 8 (87.5%) lung carcinoma cell lines and 17 of the 28 (60.7%) tumor tissues expressed high levels of M2BP mRNA. Most of the M2BP mRNA-positive cancer cell lines and tumors also showed M2BP protein expression. The serum levels of antibodies to M2BP were elevated in 30.4% of the patients. In addition, M2BP-specific immunoglobulin G was observed in all patients with anti-M2BP antibodies.

CONCLUSIONS

M2BP is highly expressed in lung carcinoma cells and is sufficiently immunogenic to elicit specific immunity to this molecule in patients with lung carcinoma. M2BP is expected to be useful as a tumor marker and a target antigen in cancer immunotherapy.

Expression of glycoprotein 90K in human malignant pleural mesothelioma: correlation with patient survival

The expression of the tumour-associated glycoprotein 90K in patients with malignant pleural mesothelioma (MM) has not been described. This study used enzyme-linked immunoassay (ELISA) to measure 90K in pleural effusions (PEs) and sera from patients with MM (n=28), lung cancer (LC) (n=14) and benign pleural disease (BPD) (n=15). Immunohistochemistry was used to investigate 90K expression in MM and LC tissue sections. The expression of 90K was further evaluated in vitro by ELISA and western blot analysis of conditioned media and cellular extracts of MM, LC and normal human mesothelial (NHM) cell cultures. Finally, the relationships between 90K expression in MM and patient age and survival were studied. The mean 90K level was significantly higher (p<0.05) in PEs of MM patients (11.0+/-6.6 microg/ml) than in LC (6.1+/-3.2 microg/ml) or BPD (6.2+/-5.0 microg/ml) patients. Immunohistochemistry showed a positive reaction for 90K in MM biopsy sections and positive staining limited to inflammatory infiltrates in LC sections. The level of 90K was significantly higher in cell culture media of MM than of LC or NHM (p<0.001). Bands representing proteins with molecular weight of approximately 90 kDa were detected by western blot in MM cellular extracts. An inverse correlation between PE 90K levels and MM patient age (r=-0.45; p=0.017) and a positive correlation between serum 90K levels and MM patient survival (r=0.62; p=0.006) were detected by linear regression analysis. Kaplan-Meier univariate analysis showed increased survival probability for MM patients with serum 90K level >7.3 microg/ml (log rank, p<0.05). This is the first report in MM of the expression of 90K and of its potential diagnostic and prognostic application.

90K (MAC-2 BP) gene expression in breast cancer and evidence for the production of 90K by peripheral-blood mononuclear cells

The tumor-derived antigen 90K (Mac-2 BP) is a widely expressed, secreted glycoprotein found in the serum of healthy individuals and at elevated levels in the serum of patients with breast cancer and other types of cancer. The precise function of 90K, particularly in the context of tumor-host relationships, has not yet been established. In this study, the clinical significance of 90K mRNA expression was studied in relation to other established prognostic parameters in 86 patients with primary breast carcinoma. The 2.2-kb 90K message was detected in all tumor samples, but there was marked variation in expression levels from tumor to tumor. Patients were classified into 2 groups on the basis of 90K expression: group 1 (n = 62) included patients with low expression, and group 2 (n = 24) consisted of patients with high expression. An inverse significant correlation was found between the levels of 90K mRNA expression and overexpression of c-erbB2/Neu receptor kinase, a marker of poor prognosis for patients with breast cancer. There was no significant difference between the groups with respect to tumor size, number of involved axillary lymph nodes, hormone-receptor status, p53 expression or proliferation activity as estimated by Ki-67 count. Similarly, no association was found between the level of 90K expression and the risk of death from breast cancer. These data are at variance with published findings showing that high serum 90K levels are associated with poor survival. Significantly, investigation of 90K-gene expression in peripheral-blood mononuclear cells (PBMC) revealed higher levels of 90K message in PBMC of breast-cancer patients than in healthy individuals. This new finding suggests that PBMC activated in response to tumor growth and progression may be an important source of serum 90K in breast cancer.

Circulating immunostimulatory protein 90K and soluble interleukin-2-receptor in human ovarian cancer

The tumor-associated antigen 90K is thought to play an important role in cellular immune defense against malignant cells. It is therefore of interest to investigate whether circulating 90K could be used as a prognostic variable in ovarian cancer, and whether this immunostimulatory antigen is related to other parameters known to be involved in the cellular immune response. In the present retrospective study, circulating levels of antigen 90K were measured before primary surgery in 152 ovarian-cancer patients. A very close association between antigen 90K and s-IL-2R concentrations was pointed out in a stepwise logistic regression model. Univariate analysis of overall survival revealed that antigen 90K and s-IL-2R were associated with poor prognosis. In the multivariate Cox regression, however, neither antigen 90K nor s-IL-2R retained independent prognostic significance. Urinary neopterin was shown to be the only independent prognostic variable among the "immunological parameters" investigated. Additionally, residual disease after primary tumor debulking and histopathologic tumor grade were the most prominent clinico-pathologic parameters for the independent prediction of poor clinical outcome in ovarian-cancer patients.