KLK4 and ovarian cancer: This discrepancy is likely due to the fact that in the study of Shih et al. [19] the secreted KLK levels were measured by ELISA while the current study analyzed gene expression levels by qPCR, suggesting that although KLK4 mRNA is expressed in ovarian cancer cells, secreted KLK4 protein may not be measurable in the extracellular environment because of the detection limit of the ELISA [19].