Increased serum level of sialyl Lewis(x) antigen in blood from the tumor drainage vein in patients with non-polypoid growth type of colorectal cancer.

ABSTRACT

Two types of colorectal cancer with distinct morphologies have been described in recent studies polypoid growth type (PG-type) and non-polypoid growth type (NPG-type). We hypothesize that the morphologic differences may correspond to additional biological distinctions. Ratios of sialyl Lewisa (CA 19-9), sialyl Lewisx (SLX), or carcinoembryonic antigen (CEA) in the venous blood drainage from the tumor to that of the respective antigen in the peripheral venous blood (d/p ratio) was examined in order to ascertain whether or not the ratio is correlated with either the PG-type or NPG-type colorectal tumor growth pattern. Blood samples from 118 patients with colorectal cancer were obtained from a peripheral vein and from the tumor drainage vein during surgical excision of the tumor. Statistical tests were conducted by univariate and multivariate (logistic regression) analyses. Among the cancers examined there were 17 PG-type (14.4%) and 101 NPG-type (85.6%). NPG-type cancers had a higher frequency of moderately differentiated adenocarcinoma cells and T3/T4 tumors than PG-type cancers (P<0.0001 and P<0.0001, respectively). NPG-type cancers had a more advanced stage than PG-type cancers (P=0.0007). The d/p ratio of SLX in NPG-type cancers was significantly higher than that in PG-type cancers (P=0.028). Multivariate logistic regression analysis showed that three variables, namely histologic type, T factor, and d/p ratio of SLX, were independently related to tumor growth patterns. In conclusion, NPG-type cancers are characterized by a high SLX d/p ratio, which may be at least partly responsible for a different tumor progression pattern compared to other cancer types.