Expression of the E-cadherin/catenin (alpha-, beta-, and gamma-) complex correlates with the macroscopic appearance of early gastric cancer

E-cadherin and its associated cytoplasmic proteins, alpha-, beta-, and gamm a -catenins, play an essential role in the control of epithelial differenti ation. We have previously shown that loss or down-regulation of E-cadherin/ catenin correlates with poor survival in advanced gastric adenocarcinoma, T he aim of this study was to assess the expression of E-cadherin and catenin s in early gastric cancers (EGCs), Immunohistochemical staining for E-cadhe rin and alpha-, beta-, and gamma -catenins was performed on 41 paraffin-emb edded gastrectomy specimens of EGC using an indirect immunoperoxidase techn ique. The pattern of expression and cellular localization of the E-cadherin /catenin complex in tumour cells were correlated with the macroscopic appea rance of the tumour according to the Japanese Endoscopic Society classifica tion. The tumours were classified as follows: three type I (protruding) and 38 type II (superficial), of which ten were type IIa (elevated), one was t ype IIb (flat), and 27 were type IIc (depressed), E-cadherin and alpha-, be ta-, and gamma -catenins were expressed at the cell-cell junctions in norma l mucosa, Forty out of 41 tumours showed abnormal expression (loss of membr anous immunoreactivity and/or nuclear staining) of at least one component o f the E-cadherin catenin complex, Loss of E-cadherin immunoreactivity was m ore frequently seen in type IIb (1/1, 100%) and type IIc (27/27, 100%) than in type I (1/13, 33%) and type IIa (1/10, 10%) (p<0.01). Abnormal expressi on of E-cadherin and <alpha>-catenin was more frequently seen in diffuse-ty pe than in intestinal type tumours (p<0.05). Abnormal immunoreactivity of < beta>- and gamma -catenin, including nuclear localization, was observed in 34% and 7.3% of tumours, respectively, but there was no significant correla tion with tumour type or endoscopic appearance. In conclusion, abnormal exp ression of the E-cadherin/catenin complex occurs in EGC and seems to correl ate with macroscopic appearances. Copyright (C) 2000 John Wiley & Sons, Ltd .