Organization and expression of the human zo-2 gene (tjp-2) in normal and neoplastic tissues

One of the tight junction components, zonula occludens protein 2 (ZO-2), is expressed as two isoforms, ZO-2A and ZO-2C, in normal epithelia. In pancre atic adenocarcinoma of the ductal type ZO-2A is absent, but none of the com mon mechanisms of gene inactivation is responsible for lack of ZO-2A expres sion. In the current study, we report the complete organization of the huma n zo-2 gene (tjp-2), its alternative splicing, and its expression in normal and neoplastic tissues of several organ sites. In addition to pancreatic a denocarcinoma, ZO-2 was found to be de-regulated in breast adenocarcinoma, but not in colon or prostate adenocarcinoma. The latter are considered to b e of acinar rather than ductal type. Thus, our data indicate the importance of zo-2 (tjp-2) gene regulation in ductal cancer development and should he lp to understand the defects of intercellular interactions, critical far su ppressing the malignant phenotype. (C) 2000 Elsevier Science B.V. All right s reserved.