Chemotherapy Response Linked to Two Genes

Cancer researchers have shown that genetic variation in two genes that code for DNA repair enzymes are linked to the survival time of patients receiving platinum-based chemotherapy for nonsmall cell lung cancer (NSCLC).

Investigators at Massachusetts General Hospital (Boston, USA) used polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to evaluate genetic polymorphisms of the XPD (Asp312Asn) and XRCC1 (Arg399Gln) DNA repair genes in 103 patients with stage III (54%) and IV (46%) NSCLC treated with platinum-based chemotherapy.

They reported in the June 1, 2004, online edition of the Journal of Clinical Oncology that while patients with no variations survived a median of 20.4 months, those with a total of three variations in the XPD and XRCC1 genes survived a median of 6.8 months. Patients with one variation survived 16.6 months, while those with two variations survived a median of 11 months.

The number of genetic variations present independently predicted length of survival irrespective of the patients' ability to carry out daily activities, their stage of disease, or the type of chemotherapy they received.
"The concept of selecting a chemotherapy drug based on a patient's genetic make-up is relatively new and very exciting,” said first author Dr. Sarada Gurubhagavatula, a physician at Massachusetts General Hospital. "We hope that this type of research will one day enable doctors and patients to make more informed decisions about chemotherapy treatments.”




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