A method for determining if a subject with cancer or precancerous lesions or a benign tumor, will respond to treatment with an inhibitor selected from the group comprising an inhibitor of one or more enzymes in the mevalonate pathway, an inhibitor of geranylgeranyl transferase, an inhibitor of farnesyl transferase or an inhibitor of squalene synthase, by (i) obtaining a sample of the cancer cells, precancerous cells or benign tumor cells from the subject, (ii) assaying the cells in the sample for the presence of a mutated p53 gene or a mutant form of p53 protein or a biologically active fragment thereof, and (iii) if the cells have the mutated p53 gene or mutant form of the p53 protein, then determining that the subject will respond to treatment with the inhibitor or combinations thereof. Some embodiments are directed to treatment with the inhibitors.
