In the experiment using an orthotopic prostate tumor model with pre-established lung metastasis, the number of metastatic lung tumors significantly decreased after the injection of Ad-REIC at the primary tumor site in addition to the inhibition of the growth of orthotopic prostate tumors, suggesting that anti-cancer immune up-regulation by Ad-REIC treatment in primary tumor sites triggered anti-tumor effects even at distant tumor site [16]. Here, DKK3 is linked to cancer.