After cancer diagnosis and treatment, the most looming concern expressed by most patients is their risk of recurrence. In the case of prostate cancer, despite screening techniques that include physical examinations, prostate-specific antigen (PSA) tests, and Gleason scoring (a grading system based on cancer cells' appearance under a microscope), oncologists often struggle with accurately stratifying patients as low-, intermediate-, and high-risk. For example, it is not clear why, following prostatectomy, some men's PSA levels rise again while others' do not.
Hampton T. New Markers May Help Predict Prostate Cancer Relapse Risk. JAMA. 2006;295(19):2234-2238. doi:10.1001/jama.295.19.2234