Opportunities for pharmacological intervention in the ras pathway.

The delineation of a ras-dependent signalling pathway from tyrosine kinases to mitogen-activated protein kinases, which is common to a variety of effectors of cell proliferation, suggests that this pathway may provide targets for agents to inhibit cell proliferation. Considerable investigation is needed to determine which points of the pathway are the most suitable for inhibition in terms of effectiveness and selectivity. The use of interfering mutants derived from each component in the pathway is one approach to determining at which point it is best to inhibit.