Abstract: The present invention relates to a novel antineoplastic agent, designated IMIC (Inhibitor of Mevalonate Incorporation Into Cholesterol) having the following characteristics:(a) is present in the retentate of dialyzed skim milk;(b) is non-dialyzable;(c) has general properties of pyrimidines;(d) is bound to a protein in the proteose-peptone fration of milk;(e) is soluble in water;(f) is insoluble in organic solvents;(g) is stable in acid;(h) is not bound or retained by a C.sub.18 or C.sub.8 reverse phase HPLC columns;(i) is not retained by a C.sub.18 or silica gel sep. pak;(j) has .lambda. maximum absorbance at 208 nm and 278 nm (UV) in neutral ad acidic solution and in a basic solution at 223 and 290 nm;(k) provides peaks with a retention time of 7.52 minutes upon fractionation by HFLC on a Biorad Aminex resin column (30 cm .times.7.9 nm) with 0.05 NH.sub.2 SO.sub.4 as the mobile phase and with a flow rate of 0.7 ml/minute;(l) provides peaks with a retention time of 9.