Prevention of experimental liver metastases by D-galactose

Summary The metastasis of malignant tumors from a primary site to near and distant secondary sites is probably the most important event in the pathogenesis of cancer and it accounts for most cancer deaths¹. Whereas advances in the treatment of primary cancer have led to increased patient survival, metastatic cancers are still the most difficult group of diseases to treat successfully². As organ-characteristic lectins play an important role in the organ manifestation of metastatic islets^3,4, it might be possible (e.g. during surgical operations on malignant tumors) to block those organ-characteristic lectins with the appropriate receptor-bearing glycoconjugates in order to inhibit the metastatic spread. Recent experiments have demonstrated that neuraminidase treatment of tumor cells (mouse sarcoma-1) alters in vivo (Balb/c-mice) the organotropic distribution of metastases; instead of being found exclusively in the lung, they are found both in lung and liver. However, pre-injection and regular application of D-galactose — the same holds for arabinogalactan^5,6,13 — prevents the settling of metastases in the liver but does not influence the metastatic process to the lung, whereas mannan — as a galactose-free control substance — does not alter the initial pattern of metastasis to lung and liver.