As depicted in Fig. 6, administration of bacteria bearing construct at concentration of 108 cfu/g body weight of mice with spontaneous breast tumors, resulted in a significant decline in expression of pro-inflammatory cytokines, including IL-1α, IL-1β, IL-6, IL-12, TNF-α, G-CSF and GM-CSF while increasing those of IL-17A, IL-10 and INF-γ compared to the PBS receiving group. This evidence concerns the gene IL17A and breast neoplasm.