ASSOCIATION OF PROGRESSION AND REDUCED EXPRESSION OF VLA-2 IN GASTRIC-CANCER

We investigated the expression of VLA-2 in gastric cancers by immunohi stochemistry using anti-integrin alpha 2 and beta 1 antibodies and the data were compared with the pathological findings of each gastric can cer. The specimens were stained with an immunohistological technique f or integrin alpha 2 and beta 1 subunits. Tumors, simultaneously expres sing both integrin alpha 2 and beta 1 subunits were defined as positiv e for VLA-2. Tumors expressing either subunits of integrin alpha 2 or beta 1 or those showing reduced expression of both subunits were defin ed as VLA-2 negative tumors. In the 77 primary tumors, 55 (71%) were V LA-2 positive. 38 (90%) of 42 tumors showing differentiated type inclu ding tubular adenocarcinoma and papillary adenocarcinoma expressed VLA -2, whereas 19 (55%) out of 35 undifferentiated type of cancers includ ing poorly differentiated adenocarcinoma, mucinous carcinoma and signe t ring cell carcinoma stained for VLA-2. In the undifferentiated type of cancers, VLA-2 negative tumors had a significantly higher incidence of vessel invasion than VLA-2 positive ones (p<0.05). VLA-2 negative tumors showed a tendency to peritoneal dissemination, lymph node metas tases, lymphatic invasion or invasion beyond the subserosal layer. In the specimens of peritoneal dissemination, VLA-2 expression rate was f ound in 56% (9/16), with a higher expression rate than that of primary lesions. These data indicate that reduced expression of VLA-2 may str ongly associate with vessel invasion especially in the undifferentiate d type of adenocarcinoma of the stomach.