Different expression of sialyl Tn antigen between polypoid and nonpolypoid growth types of advanced colorectal...

Colorectal tumors can be classified based on their growth pattern into the polypoid growth type (PG-type) and nonpolypoid growth type (NPG-type). We examined sialyl Tn antigen expression in advanced colorectal carcinomas that were classified as PG-type and NPG-type cancers in order to ascertain whether or not such expression correlates with other biologically and clinically important differences. A total of 94 advanced colorectal carcinomas were examined for sialyl Tn antigen expression, which was immunohistochemically detected by the monoclonal antibody TKH2. Univariate and multivariate analyses using logistic regression models were performed. Forty carcinomas (42.6%) were negative and 54 (57.5%) were positive for sialyl Tn antigen. Eighteen carcinomas (19.2%) were of PG type and 76 (80.8%) of NPG type. NPG-type cancers had a higher proportion of positive lymph node metastasis than PG-type cancers. Furthermore, sialyl Tn antigen was less often detected in NPG-type cancers (39 of 76; 51.3%) than in PG-type cancers (15 of 18; 83.3%; p = 0.0167). Multivariate analysis showed that two variables, lymph node metastasis and sialyl Tn antigen expression in carcinoma, were independently related to tumor growth patterns, that is NPG type and PG type. These data suggest that the difference in sialyl Tn antigen expression between two kinds of tumor growth patterns of advanced colorectal carcinomas, PG type and NPG type, may reflect different biological behaviors during tumor progression.