Abstract: The present invention relates to compositions and methods for cancer therapies and diagnostics, including but not limited to, cancer markers. In particular, the present invention provides tumor antigens associated with specific cancers and diagnostic assays for the detection of such antigens and associated autoantibodies as indicative of the presence of specific cancers. The present invention further provides cancer immunotherapy utilizing the tumor antigens of the present invention.

Abstract: The invention provides monoclonal antibodies that bind the estrogen receptor ? (ER ?) when phosphorylated at serine 118 (Ser118) in the N-terminal domain, but do not bind to ER ? when not phosphorylated at this site. Also provided are methods for determining the phosphorylation of ER ? in a biological sample, profiling ER ? activation in a test tissue, and identifying a compound that modulates phosphorylation of ER ? in a test tissue, by using the disclosed monoclonal antibodies. The sample or test tissue may be taken from a subject suspected of having cancer, such as breast cancer. Kits comprising the phospho-ER ? (Ser118) monoclonal antibodies of the invention are also provided.