Influence of methylcobalamin and cyanocobalamin on the neoplastic process in rats.

The effect of methylcobalamine (5.6-dimethylbenzimidazolyl-Co-methylcobamide, CH3-B12) and cyanocobalamine (5,6-dimethylbenzimidazolyly-Co-cyanocobamide, CN-B12) on the growth of Walker's carcinosarcoma and longevity of white noninbred rats with implanted Zajdela ascites hepatoma was studied. The two agents exerted a similar effect. They 1) reduced the survival of rats with implanted Zajdela ascites hepatoma and Walker's carcinosarcoma; 2) did not increase the cell concentration in ascites; and 3) increased the total volume of ascites.