How could pharmacogenomics help improve patient survival?

Increasing knowledge regarding multiple genetic disturbances found in human lung cancers, particularly non-small cell lung cancer (NSCLC), have enabled predictive markers to be used in specialised centres in tailoring chemotherapy regimens and improving survival and response in subgroups of patients. Impressive responses are observed in patients with epidermal growth factor receptor (EGFR) tyrosine kinase mutations following treatment with gefitinib and erlotinib; and methylation of the mitotic checkpoint gene 14-3-3sigma in circulating tumour serum DNA predicts response to cisplatin/gemcitabine therapy. Expression of markers of DNA repair, ERCC1, RRM1 and BRCA1 are also determinants of response to cisplatin/gemcitabine, with low levels of mRNA predicting improved survival. Patients harbouring the Met/Met mutation in XRCC3 240 have significantly better survival compared with other mutations. These findings are presented in this article, as well as their relevance in customising chemotherapy - illustrated by a hypothetical model guiding treatment decisions in the management of NSCLC.

Age-related genetic abnormalities: the Achilles' heel for customizing therapy in elderly lung cancer patients

Aging and cancer are closely related, and DNA repair systems, mainly involving the nucleotide excision repair pathway, have an important caretaker function in both processes. More than half of non-small cell lung cancer patients are elderly, and the expression of some genes involved in the mitotic checkpoint, such as BubR1, declines with aging. Cisplatin-based chemotherapy is the standard treatment for advanced non-small cell lung cancer; if performance status is good, both elderly and younger patients can tolerate this treatment equally well. Customized cisplatin treatment, based on reduction of the nucleotide excision repair pathway function, could be an attractive approach, and the assessment of mitotic checkpoint genes can be used for selecting docetaxel treatment. Epidermal growth factor receptor (EGFR) mutations are particularly frequent in elderly lung cancer patients who are never-smokers and constitute an attractive target for treatment with EGFR tyrosine kinase inhibitors.