Immunohistochemical expression of sialyl Tn and sialyl Lewis^a antigens in stromal tissue correlates with peritoneal dissemination in Stage IV human gastric cancer

Immunohistochemical expression of sialyl Tn antigen (TKH2 and B72.3), sialyl Lewis^a antigen (CA19-9) and CEA was examined in 52 cases with Stage IV gastric cancer, the objective being to examine whether or not these tumour-associated antigens show different expression between peritoneal dissemination and liver metastasis. Stromal type for TKH2, B72.3, CA19-9 and CEA were seen in 14 (50%), 13 (46%), 18 (64%) and nine (32%) cases with peritoneal dissemination, respectively, and in four (17%), three (13%), four (17%) and four (17%) cases with liver metastasis, respectively. The stromal type correlated to peritoneal dissemination in TKH2 (P < 0.05) B72.3 (P < 0.05) and CA19-9 (P < 0.05). In other clinicopathological factors, the stromal type for TKH2, B72.3 and CA19-9 correlated to the undifferentiated type. However, even in the undifferentiated type group, the stromal type correlated to peritoneal dissemination in TKH2 (P < 0.05), B72.3 (P < 0.05) and CA19-9 (P < 0.05). Based on these results, the spread of sialyl-rich tumour-associated antigens into the surrounding stroma in the undifferentiated type of gastric cancer may be associated with peritoneal dissemination.