Development of lectin powered lateral flow immunoassay for detection of CA 125 glycovariants in urine
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Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
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Tiivistelmä
Epithelial ovarian cancer (EOC), covering over 90 % of all ovarian cancers, is the eighth
most common malignancy in women. Due to its symptom free nature, EOC is typically
diagnosed at a late stage, with 5-year survival rate of only 30 %. With more timely
diagnosis the survival rate increases to 84 %, highlighting the crucial need for more
sensitive diagnostic methods. Cancer antigen 125 (CA 125) is a large transmembrane
glycoprotein and part of the mucin protein family. The levels of CA 125 in serum have
traditionally been used for EOC diagnostics, but it has limitations regarding its sensitivity
and specificity. CA 125 is expressed in many other malignant and non-malignant
conditions hindering specificity and its expression in EOC varies widely between the
stage and the type of tumour limiting its sensitivity.
The aim of this thesis was to develop a lateral flow (LF) assay able to detect the cancer
specific glycoform of CA 125 from urine samples. A point-of-care assay would enable
non-invasive method for monitoring treatment progression and cancer relapse. The
distinction between malignant and non-malignant CA 125 is based on the aberrant
glycosylation inherent in cancer derived biomarkers. The LF assay uses anti-CA 125
monoclonal antibodies as capture reagents and Eu+3-doped nanoparticles conjugated
either with macrophage galactose-type lectin or Wisteria floribunda agglutinin (WFA)
lectins as tracer element.
The developed LF assay utilizing WFA nanoparticles reached a limit of detection of
7.6 U/ml, which is below the clinically relevant 10 U/ml of CA 125 in urine. Two key
findings enabling this assay were the low pH 6.1 assay buffer and the pre-treatment of
urine sample by heating to combat the matrix effect caused by urine. The LF assay needs
further development especially a functioning control line and testing with clinical samples
must be performed in the future.