KLK2 and prostate cancer: Both quercetin‐treated cell lines (48 h) were studied using real‐time PCR for evaluation of VEGF isoforms (a and c) as angiogenesis‐related markers, OPN isoforms (a, b and c) as a clinically useful biomarker of tumour progression, P53 for apoptosis and Kallikrein Related Peptidase 2 (KLK2) as a prognostic marker for prostate cancer risk.