ABSTRACT
AIM: To assess kallikrein (KLK) expression in recurrent and non-recurrent prostate tumors and adjacent healthy prostate tissues. METHODS: The expression levels of 15 KLK genes in 34 recurrent and 36 non-recurrent prostate cancer samples and 19 adjacent healthy prostate tissue samples was assessed with quantitative reverse-transcription polymerase chain reaction. The samples were obtained from Baylor College of Medicine, Houston, TX, USA between 2013 and 2016. RESULTS: Compared with controls, prostate cancer samples showed a strong decrease in KLK1, KLK4, KLK9, and KLK14. Recurrent samples were negative for KLK1, KLK2, and KLK14 but demonstrated higher levels of KLK3, KLK4, and KLK9 than controls. Other KLKs were not significantly expressed. CONCLUSION: This study for the first time showed a difference in the expression levels of the KLK gene family in recurrent prostate cancer. KLKs could be used as recurrence markers for prostate cancer.