Since our data are concordant with the thesis that tumor cells that metabolize the drug will exhibit sensitivity to AF or 5F 203, the assays described, including CYP1A1 induction following incubation with unlabeled drug or induction of apoptosis, could potentially be performed ex vivo on tumor biopsies or fine needle aspirates to guide selection of patients with the greatest prospect of treatment benefit. Here, CYP1A1 is linked to neoplasm.