Glycoconjugates and tumor metastasis

Quantitative glycohistochemistry defines new prognostic markers for cancers of the oral cavity

BACKGROUND

Histopathologic grading and clinical staging cannot provide a precise prognosis of oral cavity cancer patients. The use of glycohistochemical markers may improve the level of prognostic accuracy of such conventional classification systems.

METHODS

Computer-assisted microscopy was employed in a series of 40 oral cavity cancers to determine quantitatively the percentage of positive cells, the staining intensity, and the level of staining heterogeneity for 3 glycohistochemical markers, including peanut agglutinin (PNA), Thomsen-Friedenreich antigen (T antigen) as part of a neoglycoprotein, and sarcolectin. Data were evaluated by discriminant analysis.

RESULTS

Although the level of differentiation (P < 0.01 to P < 0.001) and the T variable of the TNM staging system (P < 0.05 to P < 0.01) related mainly to the level of expression of the acceptor sites for PNA and the T antigen, the patient survival period (P < 0.05) was largely a fraction of the level of expression of the acceptor sites for the carrier-immobilized T antigen and for sarcolectin.

CONCLUSIONS

In oral cavity cancer, determining the level of acceptor sites for PNA, T antigen, and sarcolectin provides useful information on histopathologic differentiation, clinical staging, and survival. Because these processes of determination were carried out quantitatively, a discriminant model was set up, which enabled the level of oral cavity cancer aggressiveness to be characterized precisely. The current methodology described in this article should therefore afford pathologists original and quantitative (and thus objective) prognostic markers for oral cavity cancers.

Use of lectins as diagnostic and therapeutic tools for cancer

Within the past few years, lectins have become a well-established means for understanding varied aspects of cancer and metastasis. Evidence is now emerging that lectins are dynamic contributors to tumor cell recognition (surface markers), cell adhesion and localization, signal transduction across membranes, mitogenic stimulation, augmentation of host immune defense, cytotoxicity, and apoptosis. To advance understanding of these lectin-dependent processes, attempts are being made to discover new lectins that have one or more of these functions and to develop lectin- (or glycoconjugate-) based tools that could be used to home in on tumor cells. This review will summarize current research on the lectins and recent advances in the development of lectin-based diagnostic and therapeutic tools for cancer. Additionally, the future potential of lectin-based diagnosis and therapy is discussed.

Prognostic value of various molecular and cellular features in oral squamous cell carcinomas: a review

Recent findings of prognostic value for oral squamous cell carcinomas (OSCCs) which may supplement clinical staging are reviewed. Many reports show that histopathologic grading, measurements of tumor-thickness and DNA-content have independent prognostic value and may thus be of clinical value. Features regarding cells at the invading margins of the tumors are probably of higher prognostic value than features within other parts of the tumors. Reportedly, various other cellular and serum markers have prognostic associations worthwhile further research.

Loss of expression of blood group antigen H is associated with cellular invasion and spread of oral squamous cell carcinomas

Membrane-bound carbohydrates may influence the metastatic behavior of cancer cells. Forty-two squamous cell carcinomas (SCC) of the buccal and maxillary alveolar mucosa were studied retrospectively using a monoclonal antibody (BE2) that reacts with blood group H (type 2 chain) structure. H-antigen staining within the entire tumor did not correlate with the stage of the tumor, i.e., spread of the tumors. However, loss of staining within the most invasive sites of the tumors correlated significantly with the stage of tumor development and histologic grade of malignancy. These findings support the view that features relating to the cells of deeper parts of the carcinomas are very important for the clinical behavior of the tumors, and that loss of H-antigen expression is related to the stage of tumor and invasion of carcinoma cells.

Loss of expression of blood group antigen H is associated with cellular invasion and spread of oral squamous cell carcinomas

Membrane-bound carbohydrates may influence the metastatic behavior of cancer cells. Forty-two squamous cell carcinomas (SCC) of the buccal and maxillary alveolar mucosa were studied retrospectively using a monoclonal antibody (BE2) that reacts with blood group H (type 2 chain) structure and an immunoperoxidase (avidin-biotin peroxidase complex) staining technique. H-antigen staining within the entire tumor did not correlate with the stage of the tumor, i.e., tumor spread. However, loss of staining within the most invasive sites of the tumors correlated significantly with the stage of tumor development and histologic grade of malignancy. These findings support the view that features regarding the cells of deeper parts of the carcinomas are very important for the clinical behavior of the tumors and that loss of H-antigen expression is related to the stage of the tumor and invasion of carcinoma cells.

Sulfated glycoconjugate determinants recognized by monoclonal antibody, SG-1, correlate with the experimental metastatic ability of KHT fibrosarcoma cells

We have examined the binding and functional activity of monoclonal antibody (MAb) SG-1 that was raised by immunization against embryonal carcinoma cells and screened using KHT fibrosarcoma cells. Quantitative absorption, binding and in situ immunochemical staining assays indicate that the MAb SG-1-defined epitopes are expressed preferentially by the highly metastatic KHT35-L1 cells relative to the weakly metastatic, parental KHTp cells. Furthermore, there was a significant correlation (p less than 0.05) between the expression of MAb SG-1-defined antigen on the cells, following trypsin treatment, and their metastatic ability. Binding of MAb SG-1 to antigen was inhibited by specific sulfated polysaccharides including cerebroside sulfate (brain sulfatide), fucoidan, and dextran sulfate (500 kD) but not by heparan, chondroitin, keratan or dextran (5 kD) sulfates. Initial characterization of antigen from KHT cells indicates that the epitope of MAb SG-1 is defined by sulfated glycoconjugates containing galactose and sulfate but not N-acetylglucosamine. In the total lipid extracts of KHT35-L1 cells the antigen was detected in the delipidated protein fraction as well as in the chloroform/methanol fraction. These results suggest that the sulfated glycoconjugate determinants identified by MAb SG-1 may be relevant to the metastatic process of KHT fibrosarcoma cells.