Harvard pathologist Mark Rubin says such a genetic fingerprint would have far more predictive power than current methods.

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In non-small cell lung cancer, for instance, the tissue samples needed to identify these genetic markers are not routinely taken for practical reasons, says Mark Kris , an oncologist at Memorial Sloan-Kettering Hospital in New York who has worked with Iressa and with OSI's Tarceva.

FORBES: Why Cancer Drugs Need Genetic Testing