Concentration and purification of prostate cancer biomarkers envisaging an early diagnosis

• Autor(a) principal: Pedro, Sónia Isabel Neto
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/17499
• topic: Marcadores bioquímicos; Cancro da próstata; Desidrogenação

Nowadays, prostate cancer is the third most common cause of death among men. Currently, there is no effective treatment when the tumor is diagnosed at an advanced stage. Given the high mortality rates associated with cancer, the identification and quantification of tumor biomarkers in human fluids and tissues have been the subject of intense research aiming more reliable diagnoses and to avoid excessive invasive treatments. In recent years, a special interest was also raised on the simultaneous analysis of several biomarkers for the same purpose, i.e., in order to make a more accurate diagnosis. Therefore, certain tumor markers, such as prostate specific antigen (PSA) widely used for the diagnosis of prostate cancer, should be considered together with other relevant biomarkers, like lactate dehydrogenase (LDH), which has recently been indicated as an excellent prognostic and monitoring tool of treatment of the same type of cancer. Considering the current methods for the quantification and purification of these biomarkers, and since both are proteins and are present in complex biological media, they usually exhibit low selectivity and may lead to false positives or negatives. In this context, it is crucial to develop efficient and selective analytical methods for the identification and quantification of several tumor biomarkers present in the same biological sample. For this purpose, aqueous biphasic systems (ABS) composed of ionic liquids (ILs) were investigated as an alternative extraction and purification technique for these biomarkers from synthetic and real biological fluids. In this work, novel ABS capable of extracting and concentrating PSA from human urine, and SAB capable of extracting and purifying LDH from human serum, in a single-step, were identified, allowing thus the identification and quantification of both biomarkers in biological fluids using more expedite analytical equipment, such as size-exclusion high-performance liquid chromatography (SE-HPLC).