Development of an immunoluminescence assay to detect Glypican 1 in urine cells, as a candidate biomarker for diagnosis of prostate cancer

Among the cancers of the urinary tract in men, prostate cancer is the most common and with the second highest mortality rate if not detected on time. The current protocol for prostate cancer diagnosis includes a screening blood test for prostate specific antigen (PSA), which is problematic due to its low specificity. Patients who present high levels of PSA undergo invasive procedures that are often unnecessary. Voided urine is the biological source of choice for the investigation of biomarkers for cancers of the urinary tract. GPC1, also known as Glypican 1, is a cell surface glycoprotein involved in cell division and growth regulation. It has been linked to some types of cancers, such as pancreas, breast and prostate. The main goal of this work was to develop an assay platform in order to determine whether GPC1 has potential as a biomarker for detection of prostate cancer in voided urine sediments samples. MIL38 is a mouse monoclonal antibody, originally raised against a bladder cancer cell line, that binds to GPC1; it is used as the core tool for this work. A fluorescence immunoassay for urine sediments was developed using MIL38 to detect GPC1 positive cells. Autofluorescence and low cells numbers generated bias in the study, which was otherwise promising. To overcome these problems, optimisation in the sample processing was done and upconversion nanoparticles (UCNP) and luminescent europium chelates tools were explored to develop an immunoassay to eliminate autofluorescence interference.