Different expression of sialyl tn antigen between polypoid and nonpolypoidgrowth types of advanced colorectal carcinoma

Colorectal tumors can be classified based on their growth pattern into the polypoid growth type (PG-type) and nonpolypoid growth type (NPG-type). We e xamined sialyl Tn antigen expression in advanced colorectal carcinomas that were classified as PG-type and NPG-type cancers in order to ascertain whet her or not such expression correlates with other biologically and clinicall y 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 analy ses using logistic regression models were performed. Forty carcinomas (42.6 %) were negative and 54 (57.5%) were positive for sialyl Tn antigen. Eighte en 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-t ype 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 meta stasis and sialyl Tn antigen expression in carcinoma, were independently re lated to tumor growth patterns, that is NPG type and PG type. These data su ggest that the difference in sialyl Tn antigen expression between two kinds of tumor growth patterns of advanced colorectal carcinomas, PG type and NP G type, may reflect different biological behaviors during tumor progression . Copyright (C) 2000 S. Karger AG, Basel.