KLK3 and prostate cancer: In the current study, quantitation of gene signatures for the early endosomal genes APPL1, EEA1 and RAB5A, and analysis of the endosomal genes MYO1B, PDCD6IP and STX12 in prostate cancer patients expressing PSA ≤ 10 ng/mL, led to patient stratification into high and low-risk recurrence groups.