A novel, nuclear pore-associated, widely distributed molecule overexpressed in oncogenesis and development

Nuclear pore complexes are large, elaborate macromolecular structures that mediate the bidirectional nucleocytoplasmic traffic. In vertebrates, nuclea r pore complexes comprise 50 to 100 proteins termed nucleoporins (Nup). An 88-kd nucleoporin (Nup88) has been recently cloned and characterized, and f ound to be associated in a dynamic subcomplex with the oncogenic nucleopori n CAN/Nup 214. We have produced a polyclonal antiserum to Nup88, and found that it immunoreacts convincingly in conventional tissue sections of 214 sa mples of malignant tumors of many types. All carcinomas were stained irresp ective of site or line of differentiation; the majority of cases reacted st rongly and extensively, In situ carcinomas and highly dysplastic epithelia were similarly reactive. Samples of malignant mesotheliomas, gliomas, sarco mas, and lymphoreticular tumors were also stained. Substantial reactions we re also found in certain fetal tissues, Focal reactions were noted in some reactive-proliferative processes. Most benign epithelial and mesenchymal tu mors and hyperplasias, and normal adult tissues reacted weakly and sporadic ally or not at all. Immunoblot analysis of selected samples strongly corrob orated those findings. If further substantiated, our findings indicate that Nup88 could be regarded as a selective yet broadly based proliferation mar ker of potential significance in the histological evaluation and diagnosis of malignant transformation. Its ready applicability on conventional paraff in sections acid on cytological preparations may broaden its clinical and i nvestigative significance.