KLK3 and prostate carcinoma: Similarly, for 358 patients who had biochemical evidence of recurrence of prostate cancer and underwent 11C–choline PET/CT, authors [26] found that the GS was a less robust predictor of positive scan results than the trigger PSA; however, most of the patients (257/358, or 72%) in this series also had a GS of less than or equal to 7.