Abstract: All neoplastic cells express one or more members of a unique family of cell surface ubiquinone (NADH) oxidase proteins with protein disulfide-thiol interchange activity (ECTO-NOX proteins) that are characteristically inhibited by quinone site inhibitors with anti-cancer activity. Cancers of different cellular or tissue origins express different tNOX cancer isoforms or combinations of isoforms and shed these proteins into the circulation. Herein are disclosed methods both for cancer detection and diagnosis of particular origin, based on the patterns and molecular weights of the isoforms which allow the identification of the cell type and or tissue of origin of the neoplasm. Relative tNOX amounts are proportional to tumor burden and provide a reliable measure of response to therapy and disease progression.

Abstract: The present Specification describes compositions and methods for production of a recombinant single chain variable region (ScFv) antibody useful for the detection of members of the ECTO-NOX family of cell surface proteins on Western blots. This single chain antibody is especially useful in the detection, diagnosis and monitoring of neoplastic disorders. A linker sequence required to appropriately combine the light and heavy chain variable region fragments to form the functional recombinant single chain antibodies is also provided. The resultant ScFv is a pan ECTO-NOX antibody for detection on Western blots of most if not all tNOX isoforms.