KLK3 and prostate cancer: Based on diagnostic performance, often confirmed histologically [1, 2], 18F-fluciclovine (anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid (18F-FACBC), Axumin®, Blue Earth Diagnostics, Burlington, MA) was approved in the US in May 2016 as a tracer for “positron emission tomography (PET) imaging in men with suspected prostate cancer recurrence based on elevated blood prostate-specific antigen (PSA) levels” post-treatment [3].