PAX8 antibody is expressed in a high percentage of renal cell carcinomas and ovarian cancers. PAX8 [BC12] has been designed to target restricted epitopes and exhibits higher specificity and provides sharper staining than the PAX8 rabbit polyclonal antibody. PAX8(M) stains nuclei exclusively and does not stain B-cells, nor does it recognize epitopes of pancreatic origin and neuroendocrine cells in stomach and colon. The expression of the mouse monoclonal PAX8 target antigens was found in normal kidney, thyroid and cervix, but was not identified in normal ovary. By western blot, [BC12] has been shown to recognize PAX8 and not PAX2, PAX5 or PAX6 proteins. US Patent 8,852,592 and patents pending.