Małgorzata Przybyło

By Małgorzata Przybyło, Marcelina E. Janik and Dorota Hoja-Łukowicz

Malignant melanoma is the sixth most commonly diagnosed cancer in developed countries. Like in many cancers, survival rates are closely associated with the time of melanoma detection. Regrettably, most cases of melanoma are caught at diffuse state and methods used in clinical practice and experimental trials are not effective. Thus, there is a great interest in discovering biomarkers that could be used for screening those with melanoma, as prognostic and prediction factors as well as new potential targets for melanoma treatment. For this purpose, many groups have examined alteration in the structure and expression of carbohydrate part of glycoconjugates to identify changes that occur with melanoma. The observed changes include increased β1,6 branching correlating with higher abundance of polylactosamine extension, increased sialylation accompanied by differences in the position of sialic acid residues, increased fucosylation, higher levels of T and Tn antigens as well as changes in the expression of ganglioside structures. As a consequence of glycan modification, the loosened matrix adhesion, increased motility, higher invasive potential and metastasis formation have been observed. Growth and migration of melanoma cells have been also found to be stimulated by advanced glycation end products. Biomarker discovery is a multi-step process and the recent glycomic data on melanoma are mostly related to the discovery phase, as the first one leading to validation and standardisation steps.

Part of the book: Human Skin Cancer, Potential Biomarkers and Therapeutic Targets

By Marcelina E. Janik, Dorota Hoja-Łukowicz and Małgorzata Przybyło

Cadherins are a large family of Ca2+dependent adhesion proteins. They are transmembrane or closely related to membrane glycoproteins localized in specialized adhesive junction. The expression of various cadherins may be concomitant with cancer progression steps and the term ‘cadherin switch’ has been created due to the observation of down-regulation of E-cadherin (suppressor of metastatic potential) and up-regulation of N-cadherin (promoter of metastatic potential) expression during tumour progression. These changes are thought to be closely related to epithelial-to-mesenchymal transition of cells of many different types of cancer including skin cancers, and accompany the increase of their motility and invasion abilities resulting in the metastasis formation. The cadherin polypeptide is a potential substrate for post-translational modification, for example, N-glycosylation, and its important role in the regulation of cadherin function has been described. The changed glycosylation of cadherins has been described in various skin cancers including melanoma and was consistent with cadherins’ role in epithelial-to-mesenchymal transition. The detailed analysis of cadherin expression and cadherin-related glycosylation changes taking place during malignant transformation could be a key for better understanding of the nature of this process and may open new opportunities for the creation of more effective anticancer therapeutics and diagnostic tools.

Part of the book: Human Skin Cancer, Potential Biomarkers and Therapeutic Targets