KLK3 and cancer: For the immunotherapy of prostate cancer (PCa), the second most common cause of cancer death among men in the United States, a recombinant live attenuated L. monocytogenes strain (Lm–LLO–PSA) expressing human prostate-specific antigen (PSA) was found to elicit strong immune responses toward PSA and regress established tumors in a murine model, indicating its potential application as a therapeutic vaccine (Shahabi et al., 2008).