Immunochemical Assays and Nucleic-Acid Detection Techniques for Clinical Diagnosis of Prostate Cancer

Abstract

Prostate cancer (PCa) is a significant cause of morbidity and mortality and the most common cancer in men in Europe, North America, and some parts of Africa. The established methods for detecting PCa are normally based on tests using Prostate Specific Antigen (PSA) in blood, Prostate cancer antigen 3 (PCA3) in urine and tissue Alpha-methylacyl-CoA racemase (AMACR) as tumour markers in patient samples. Prior to the introduction of PSA in clinics, prostatic acid phosphatase (PAP) was the most widely used biomarker. An early diagnosis of PCa through the detection of these biomarkers requires the availability of simple, reliable, cost-effective and robust techniques. Immunoassays and nucleic acid detection techniques have experienced unprecedented growth in recent years and seem to be the most promising analytical tools. This growth has been driven in part by the surge in demand for near-patient-testing systems in clinical diagnosis. This article reviews immunochemical assays, and nucleic-acid detection techniques that have been used to clinically diagnose PCa.

Keywords: Biopsy; Clinical Diagnosis; Immunoassays; PAP; PSA.; Prostate Cancer.

Figure 1

Schematic representation of PAP timeline (adapted from 27).

Figure 2

Schematic representation of the biosynthesis of PSA in normal and cancerous epithelial tissues of the prostate (adapted from 29).

Figure 3

The specificity and probability of prostate health index (PHI) (adapted from 46).

Figure 4

The PCA3 test assay and score.

Figure 5

Multi-enzyme magnetic particle-labelled antibody detection strategies for the detection of serum biomarkers: (A) immunosensor after incubating with protein analyte in a flowing conventional single-enzyme labelled antibody; (B) immunosensor after offline capture of protein analyte with heavily labelled antibody and enzyme. The enzyme-antibody-protein analyte is trapped by capture antibodies (adapted from 98).