KLK3 and cancer: In this respect, the “Holy Grail” of cancer researchers and bioengineers for decades has been molecular sensing probes that would allow for the diagnosis, prognosis, and monitoring of cancer diseases via their interaction with tumor-associated cancer cells and/or blood-solubilized PC biomarkers, such as the prostate-specific antigen (PSA), the prostate cancer antigen 3 gene (PCA3), and sarcosine oxidase [2,10,11,12,13,14,15,16].