KLK3 and cancer: As a measure of outcomes, growth rates estimated using the g-rate method have been shown by us and the US FDA to highly correlate inversely with OS in numerous cancers treated with chemotherapy, targeted therapies, and immunotherapy.21,26,27,28 Additionally, we demonstrate that we can calculate g-rate as early as 3 months if there are at least 3 serial PSA values available 2 to 3 weeks apart within that timeframe.