TLR9 was shown over-expressed in hormone-regulated cancers (e.g., breast, ovary and prostate cancers) where it showed by contrast a relationship with a poor prognosis; in these cases the increasing expression of estrogen receptor (ERα) have been reported to lead to the decreased expression and function of TLR9 with a beneficial effect against tumor invasion [47]. Here, TLR9 is linked to prostate carcinoma.