The expression of Lewis(a) and Lewis(b) antigens reflects changes in fucosylation between normal and neoplastic cervical squamous epithelium

The Diverse Contributions of Fucose Linkages in Cancer

Fucosylation is a post-translational modification of glycans, proteins, and lipids that is responsible for many biological processes. Fucose conjugation via α(1,2), α(1,3), α(1,4), α(1,6), and O'- linkages to glycans, and variations in fucosylation linkages, has important implications for cancer biology. This review focuses on the roles that fucosylation plays in cancer, specifically through modulation of cell surface proteins and signaling pathways. How L-fucose and serum fucosylation patterns might be used for future clinical diagnostic, prognostic, and therapeutic approaches will be discussed.

Sialyl Lewis x expression in cervical scrapes of premalignant lesions

Sialylated oligosaccharides of glycoproteins and glycolipids have been implicated in tumour progression and metastases. Altered expression of glycosidic antigens has been reported in cervical cancer. In cervix premalignant lesions, an increased expression of sialic acid has been reported. In the present study we determined the expression profiles of the glycosidic antigens Tn, sialyl Tn (sTn), Lewis a (Lea), sialyl Lewis a (sLea), Lewis x (Lex) and sialyl Lewis x (sLex) in cervical scrapes with cytological diagnoses of normal, low-grade squamous intraepithelial lesions (LGSIL) and highgrade squamous intraepithelial lesions (HGSIL). Cervical scrapings were collected to detect tumour antigens expressions by flow cytometry using monoclonal antibodies. Cytometry analysis of Tn, sTn, Lea and Lex did not reveal differences at the expression level among groups. The number of positive cells to sLea antigen increased in the HGSIL group with respect to the normal group (p=0.0495). The number of positive cells to sLex antigen in the samples increased with respect to the grade of squamous intraepithelial lesion (SIL) (p less than 0.001, Mann-Whitney U test). The intensity of expression of this antigen increased in the HGSIL samples with respect to normal samples (p less than 0.0068). sLex antigen could be a candidate to be used as biomarker for the early diagnosis of cervical cancer.

Losses of expression of the antigens A, Lea and Lex and over-expression of Ley in carcinomas and HG-SIL of the uterine cervix

BACKGROUND

The glycosylation of a great number of molecules, glyco-protein or glycolipids, has been of interest for decades.

OBJECTIVE

To compare the expressive patterns of the isoantigenic determinants of histo-blood groups ABH and Lewis in squamous and simple epithelium and in precursors and cancers of the cervix.

METHODS

A total of 36 lesions and neoplasms (10 LG-SIL, 16 HG-SIL and 10 invasive carcinomas) have been studied with immunohistochemical techniques, using monoclonal antibodies (MoAb BG1 to BG8) for precursor chains, blood-group ABH and Lewis group Le(a), Le(b), Le(x), and Le(y), and four types of lectins. In addition, we have studied the expression of p53 protein and PCNA, establishing the rate of proliferation of each lesion. Using PCR techniques, we have also detected part of the intron of the E6 gene of HPV-16.

RESULTS

In the invasive cervical carcinomas, we observed a loss of expression of the Le(x) antigen (p < 0.01). With regard to the progression of the different lesions studied, we found alterations in the patterns of expression of the antigens of the ABH and Lewis blood groups. There was a tendency towards a loss of expression and heterogeneous patterns in the more advanced lesions, as well as over-expression of the Le(y) antigens. With PCNA, we established a proliferative rate which tended to be greater in relation to the progression of the cervix neoplasms.

CONCLUSION

These results indicate that there is a relation between the losses of histo-blood groups and the progression of the squamous intraepithelial lesions.

Lewis blood group and CEA related antigens; coexpressed cell-cell adhesion molecules with roles in the biological progression and dissemination of tumours

The Lewis blood group and carcinoembryonic antigen (CEA) related antigens have adhesive functions in human tissues, with roles in embryonic sorting and migration of cells (organogenesis), differentiation and protection of normal mucosal tissues, migration of neutrophils, bacterial binding, and tumour differentiation and dissemination. In the key areas of mucosal protection, neutrophil binding, and tumour metastasis, they are often coexpressed on the outer cell membrane, with Lewis blood group antigens forming the terminal carbohydrate chains on a CEA related glycoprotein backbone. The central role of these antigens in the mechanism of neutrophil binding to endothelium in inflammation highlights a fascinating paradigm for tumour cell dissemination and metastasis, and expression is linked to disease prognosis. This review outlines the structure, function, and comparative roles of these antigens in human tissues.

Membranous expression of carcinoembryonic antigen (CEA) in the normal cervical squamous mucosa

Using a panel of polyclonal and monoclonal antibodies to CEA-related antigens in paraffin-processed cervical biopsies, CEA and NCA expression has been demonstrated on the cell membrane of normal mature cervical squames. Cytofluorimetry of disaggregated cervical squames confirmed membranous expression and immunogold labelling of ultrathin cryostat sections localized CEA to the glycocalyx and to within cytoplasmic membrane-bound vesicles of mature squames. Immunoblotting of cervical tissue showed that most of the CEA reactivity was expressed as a glycoprotein of molecular weight around 180 k, probably CEA itself. Localization of the CEA to the cell membrane of mature cervical squames suggests a key role for these antigens in maintaining the integrity of the squamous mucosa, through the putative function of an adhesion molecule.