Novel phenyl-substituted tricyclic compounds of formula (1.0) and pharmaceutical compositions are disclosed which are inhibitors of the enzyme, farnesyl protein transferase. Also disclosed is a method of inhibiting Ras function and therefore inhibiting the abnormal growth of cells. The method comprises administering the novel halo-N-substituted urea compound to a biological system. In particular, the method inhibits the abnormal growth of cells in a mammal such as a human.