This antibody reacts with human and mouse c-myc protein, which is a nuclear protein with a molecular weight of approximately 66 kDa. This antiserum detects c-myc by immunoblotting assays in both overexpressed and endogenous systems. Reactivity in other immunoassays has not yet been fully determined although perinuclear and cytoplasmic staining has been reported. The recommended positive controls are SK-BR-3 cells (adenocarcinoma, breast, malignant pleural effusion, human).