THE FIBRONECTIN ISOFORM CONTAINING THE ED-B ONCOFETAL DOMAIN - A MARKER OF ANGIOGENESIS

Different fibronectin (FN) isoforms are generated by the alternative s plicing of 3 regions (ED-A, ED-B and IIICS) of the primary transcript. The FN isoform containing the ED-B sequence, a complete type-III-homo logy repeat, while having extremely restricted distribution in normal adult tissues, reveals high expression in fetal and tumor tissues. Usi ng the monoclonal antibody (MAb) BC-I, specific for the FN isoform con taining the ED-B sequence (B+ . FN), we demonstrate here, using immuno histochemical techniques, that while this FN isoform is undetectable i n mature vessels, it is highly expressed during angiogenesis both in n eoplastic and in normal tissues, as in the case of the functional laye r of endometrium during the proliferative phase. B+ . FN is thus a mar ker for the formation of new vessels, and the BC-I MAb may be a useful reagent for evaluating the level of the angiogenetic process in diffe rent neoplasms. (C) 1994 Wiley-Liss, Inc.