Investigation of Three Biomarkers for the Detection of Prostate Cancer

Worldwide, prostate cancer is the most commonly diagnosed cancer in men and the fifth leading cause of cancer death in men. This amounted to 1,414,249 newly diagnosed cases and 375,000 deaths worldwide yearly from this disease in 2020. Globally, prostate cancer is the most commonly diagnosed cancer in more than fifty percent of countries (112 of 185). It presents a significant clinical burden in terms of volume and as a diagnostic challenge.

The initial diagnosis of prostate cancer relies on the detection of PSA (prostate specific antigen) in patient blood. While PSA is relatively good at identifying prostate cancer, PSA levels can be elevated for reasons other than cancer (giving a false positive result). Two thirds of men with a raised PSA level don't have prostate cancer meaning that many men undergo unnecessary \& invasive follow up procedures, such as tissue biopsy. Prostate biopsies place a huge burden on both healthcare systems, and individuals with suspected prostate cancer. They are painful, can lead to complications, infections and in extreme circumstances, death.

Therefore, the poor specificity of the PSA test, combined with the disparate natural histories of many prostate cancers has limited its utility as a screening tool.

A combination of clinical and pathological features, such as the tumour grade (Gleason score or Gleason Grade Group), combined with clinical examination (digital rectal examination), MRI (magnetic resonance imaging) and isotope bone scan are commonly used to determine the aggressiveness and curability of tumours with radical treatment. PSA measurement is used as part of this assessment but, as other factors can influence PSA levels, it cannot be used to assess risk or guide treatment in isolation.

There remains an unmet clinical need for a better screening and diagnostic test for prostate cancer. Such a test must also be able to differentiate between early, low-risk cancers that do not require radical treatment and more aggressive tumours where radical treatment is preferable. By identifying which patients have a clinically significant risk of prostate cancer we believe our test could provide a solution to both.

The GlycoScore immunoassays detect the three biomarkers - 'glycosyltransferase enzymes' in patient blood (GALNT7, ST6GAL1 and GCNT1) which are linked to key tumour-associated glycans (types of sugars on cell walls) using an ELISA (enzyme-linked immunosorbent assay-based platform).

Initial studies conducted by Newcastle University using RUO (research use only) ELISA kits showed a significant correlation between prostate cancer and the three biomarkers ST6GAL1, GCNT1 and GALNT7. Extensive research and development work has been carried out developing custom antibody pairs and antigens for inclusion in our ELISA kit, as well as to optimize buffers and other components.

The purpose of this study is to obtain fresh patient blood samples to further evaluate the three biomarkers ST6GAL1, GCNT1 and GALNT7 for their ability to identify clinically significant prostate cancer, either alone, as a combination of the biomarkers or in combination with the PSA (measurement obtained at Medtechtomarket) using our in-house developed ELISA assays and a CE-marked PSA ELISA test kit.

Diagnostic accuracy for participants with prostate cancer will be determined by comparison with biopsy results, and for participants without prostate cancer, comparison with mpMRI (multi-parametric magnetic resonance imaging) and biopsy results.

Assessment of the correlation between the GlycoScore biomarker results with the full range of biopsy Gleason scores/Gleason Grade group/CPG grade (Cambridge Prognostic Group) will allow an assessment of the prognostic value of the GlycoScore test and its potential use in the clinical management of prostate cancer.

Patients attending the hospital for a transperineal prostate biopsy who are either being investigated for suspected prostate cancer or are undergoing active surveillance for previously diagnosed prostate cancer will be asked to consent to take part in the study. Patients will be asked to consent to have a small sample of blood taken before the biopsy and for study investigators to have access to their final diagnosis. The blood sample will be sent to Medtechtomarket Laboratories for measurement of the biomarkers and PSA. Patients will also be asked to consent to an additional tube of blood to be taken (from the same blood draw) and the urine sample, which is routinely taken before the biopsy to be sent to the Liverpool University Biobank for future use in research studies.

137 male patients aged 18 years and above will be recruited for the study which is expected to take 12 months.

• Establishment of a 'GlycoScore' algorithm [Time frame: Pre-biopsy (one time point)]
• An evaluation of the ability of the calculated 'GlycoScore' to distinguish between individual Gleason scores and grade groups [Time frame: Pre-biopsy (one time point)]
• An evaluation of the ability of the calculated 'GlycoScore' to distinguish between CPG groups 1 to 5 (Cambridge Prognostic Group classification) [Time frame: Pre-biopsy (one time point)]
• A comparison of the diagnostic performance of the GlycoScore biomarkers (with and without PSA) against the performance of the hospital PSA test alone for the detection of clinically significant prostate cancer (Gleason score of ≥7). [Time frame: Pre-biopsy (one time point)]