Recognizes a protein of 14-16 kDa, which is a novel nuclear antigen of proliferating cells. IPO-38 antigen is present in the nuclei of proliferating cells such as Hodgkin's disease and non-Hodgkin's lymphomas, different forms of leukemias, breast and colorectal carcinomas, and PHA-stimulated lymphocytes. It is not expressed in the cells of non-stimulated lymphocytes and granulocytes. IPO-38 may be a useful marker of cell proliferation during monitoring of tumor progression. This antibody is available purified with BSA/azide at 200 ug/mL, or BSA/azide-free at 1 mg/mL.