The present invention relates to the discovery that inhibition of Dickkopf2 (DKK2) increases CD8+ cytotoxic T lymphocyte (CTL) activity, attenuates tumor angiogenesis, and hence suppresses tumor formation. Thus, in various embodiments described herein, the methods of the invention relate to methods of treating cancer by administering to a patient an effective amount of DKK2 gene depleting agent, methods for providing anti-tumor immunity and anti-tumor angiogenesis in a subject, methods of stimulating a T cell mediated immune response to a cell population or a tissue and suppressing tumor angiogenesis in a subject. Additionally, the current invention includes methods of diagnosing a cancer or a predisposition of developing a cancer or a metastasis and methods for determining the use of immunotherapy treatment or cancer vaccine for treating cancer. Furthermore, the invention encompasses a pharmaceutical composition for treating cancer as well as a kit for carrying out the aforementioned methods.