A purified DOC1 polypeptide comprising a fragment of SEQ ID NO: 1 is provided, wherein the DOC1 polypeptide is not the full-length DOC1 polypeptide sequence. A method of inhibiting angiogenesis in a subject is provided comprising administering to a subject a nucleic acid encoding a DOC1 polypeptide, whereby a cell in the subject produces the DOC1 polypeptide, thus inhibiting angiogenesis. A method of inhibiting tumor growth in a subject is provided comprising administering to a subject a nucleic acid encoding a DOC1 polypeptide, whereby a cell in the subject produces the DOC1 polypeptide, thus inhibiting tumor growth.
