KLK3 and neoplasm: Furthermore, fusion of the antigen (for example, the epidermal growth factor receptor family of tyrosine kinases, HER-2/neu; prostate-specific antigen, PSA and so on) to dtLLO or ActA (encoded by the actA gene) and secretion by L. monocytogenes was found to significantly enhance anti-tumor immune responses in comparison to an LM vector that secreted only the tumor antigen (Singh et al., 2005; Shahabi et al., 2008).