Numerous studies have examined whether a tumour specific glycan signature on prostate specific antigen (PSA) can be used to distinguish between BPH and PCa (Gilgunn et al., 2013) and there are ongoing studies analysing the glycan composition of serum, plasma, exosomes, expressed-prostatic secretions (EPS) fluids and formalin-fixed, paraffin-embedded (FFPE) tissues to diagnose PCa and determine prognosis (Yoneyama et al., 2014, Kyselova et al., 2007, Drake and Kislinger, 2014, Powers et al., 2013, Powers et al., 2014, Drake et al., 2015). The gene discussed is KLK3; the disease is benign prostatic hyperplasia.