Kallikrein-related peptidase 4 (KLK4) initiates intracellular signaling via protease-activated receptors (PARs). KLK4 and PAR-2 are co-expressed during prostate cancer progression.
Kallikrein 4 (hK4) and prostate-specific antigen (PSA) are associated with the loss of E-cadherin and an epithelial-mesenchymal transition (EMT)-like effect in prostate cancer cells.
CD4 T cell clones specific for these epitopes are shown to efficiently and specifically recognize both recombinant KLK4 protein and lysates from prostate tumor cell lines virally infected to express KLK4.
In this study, KLK4 gene expression in human prostate tumors was further characterized using cDNA quantitative PCR and immunohistochemistry, demonstrating that the gene is specifically expressed at both the mRNA and protein levels in normal human prostate tissue, and in both primary and metastatic prostate tumor samples.