Abstract: The invention relates to a method for the treatment of cancer by changing the intracellular activity of cdc42. The activity can be increased by treatment with small molecules, for instance, treatment with non-hydrolyzable GTP-analogues of cdc-42. Also, the activity can be increased by inhibiting nm23-H1 and/or nm23-H2, which are factors having an inhibitory effect on the expression and/or activity of cdc-42. It is also shown that a decrease in the intracellular activity of cdc-42 has a beneficial effect. Further embodiments of the invention are the compounds for use in such methods, pharmaceutical preparations comprising such compounds and use of such compounds for the preparation of a medicament for treatment of cancer.