Microarray technology could be used to tailor therapy according to theindividual, and prevent breast cancer patients from having to undergo painfulunsuccessful therapies. In a study published in the journal Breast CancerResearch, researchers analysed tumour tissue samples and identified a group of64 genes that can be used to predict a patient's response in the five yearsafter adjuvant therapy for breast cancer. Identifying patients whose breasttumours express these genes could potentially be used to predict which patientswould not benefit from adjuvant therapy, and avoid patients being giventherapies with the potential of causing more harm than good.
A team of researchers led by Jonas Bergh from the Karolinska Institutet inStockholm, Sweden, analysed the gene expression profiles of 159 breast cancerpatients using DNA microarray analysis. From these samples they identified thegenetic signatures shown by 38 patients who had a poor prognosis - defined asrelapse or death from any cause within 5 years. The remaining 121 patients weredefined as the 'good prognosis' group. The researchers also used gene expressionprofiling to separate patients who did well with and without adjuvant therapy,and those whose tumours failed to respond to treatment.
An analysis of the genes expressed in the tumours of all 159 patients showedthat 64 genes were used to separate the patients with good and poor prognoses.The researchers then tested the predictive value of the group of 64 genescompared with three currently used clinical markers. Using the expressionpatterns of the 64 genes identified by the researchers gave significantly better(P=0.007) prediction rates than histological grading, tumour stage and age -which are all accepted prognostic markers for breast cancer.
The present lack of criteria to help tailor breast cancer treatment toindividual patients indicates a need to develop new techniques for betterprediction of how patients will respond to adjuvant treatments. The researcherssuggest that the technique of DNA microarray analysis could be developed to helpbreast cancer patients who do not benefit from adjuvant therapy, and avoidpainful unnecessary treatments and wastage of healthcare resources.
Gene expression profiling spares early breast cancer patients fromadjuvant therapy - derived and validated in two population-based cohorts
Yudi Pawitan, Judith Bjφhle, Lukas Amler, Anna-Lena Borg, Suzanne Egyhazi, PerHall, Xia Han, Lars Holmberg, Fei Huang, Sigrid Klaar, Edison T. Liu, LanceMiller, Hans Nordgren, Alexander Ploner, Kerstin Sandelin, Peter M. Shaw,Johanna Smeds, Lambert Skoog, Sara Wedrιn, Jonas BerghBreast Cancer Research, in press
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