In 2014 study "Human kallikrein-2 gene and protein expression predicts prostate cancer at repeat biopsy" rs198977 T allele was found associated with prostate cancer at repeat biopsy with 1.8 odds ratio (95% CI: 1.04-3.13, p = 0.049). High serum hK2 level (> 0.163 ng/mL average in the study) correlated with rs198977, and combined they predicted prostate cancer with OR 3.77 (95% CI: 1.94-7.32, p <0.0001). However, addition of these factors did not significantly improve existing baseline model with age, ethnic background, PSA, DRE, past histology, prostate volume, and family history as risk indicators. This study was conducted with quite selective sample group of 941 patients and is likely not applicable to general population, however it does convincingly back up the association found in earlier studies.
[PMID 20424135] Blood Biomarker Levels to Aid Discovery of Cancer-Related Single-Nucleotide Polymorphisms: Kallikreins and Prostate Cancer
[PMID 21178268] Exploratory study of a KLK2 polymorphism as a prognostic marker in prostate cancer
[PMID 17085659] Variants of the hK2 protein gene (KLK2) are associated with serum hK2 levels and predict the presence of prostate cancer at biopsy.
[PMID 20514297] 2010 CUA Abstracts.
[PMID 24270797] Genetic variation in KLK2 and KLK3 is associated with concentrations of hK2 and PSA in serum and seminal plasma in young men