The invention relates to cerium compounds having general formulas (I) Rni+Yin-;
and (II) Rb+Yb+ and their application
as medicaments in the prophylaxis and/or treatment of cancer diseases. In formula
(I), R is a group of general formula (A):
##STR1##
and in formula (II), Rb is a group of general formula (B)
##STR2##
