Glycoconjugates and tumor metastasis.

Abstract

Metastasis is one of the most dangerous characteristics of malignant tumors, and it seems to be a biological property separate from rapid and uncontrolled growth. The clinical significance of metastasis as opposed to tumor growth was suggested when we studied the records of 391 colorectal cancer patients surgically treated at The University of Texas M. D. Anderson Hospital and Tumor Institute between 1959 and 1975 to see if there was any correlation between the size of a primary tumor and the incidence of local or distant metastasis. The mean size of primary tumors from patients having regional or distant metastasis was significantly smaller than the mean size of primary tumors from patients without metastasis (Miller et al., 1985), and the five-year survival rate of patients having metastasis at the time of surgery was much poorer than that of patients having no metastasis (Miller et al., 1985). These results indicated that metastatic capacity, not rapid proliferation, is the major cause of death by colorectal cancer. This hypothesis is presumably true for many other malignant tumors. The other important conclusion drawn from this study was that the tumor cells of each colorectal carcinoma may be unique in their metastatic potential. In addition, intratumoral heterogeneity may exist. These findings are consistent with the biological nature of metastatic tumors as determined in experimental tumor systems (Nicolson and Poste, 1982, 1983).