Date Published: 10 August 2005
Patient's genes may be used to predict response to chemotherapy for breast cancer
Yesterday, 9th August 2005, research suggesting the possibility of testing patient genes in order to predict the response of breast cancer to chemotherapy treatment was published in the Journal of Translational Medicine.
Research Techniques / Procedure
Olga Modlich and colleagues, from the University of Düsseldorf
and Bayer HealthCare AG in Germany, analysed samples of breast tissue
from five healthy individuals and tumour tissue from fifty-six breast
cancer patients treated with preoperative systemic chemotherapy (PST)
with a combination of the anti-cancer drugs epirubicin and cyclophosphamide.
The genes present in the samples were analysed using a DNA microarray
- a collection of microscopic DNA spots attached to a solid surface used
to measure the expression levels of large numbers of genes simultaneously.
From the DNA microarray analysis the authors were able to identify a total of fifty-seven 'predictor' genes active in tumours: thirty-one genes associated with a favourable response and twenty-six genes associated with a poor response. The authors then tested the ability of these genes to predict the response of twenty-seven breast cancer patients, who were then treated with PST.
The predictor genes could be used to correctly predict the outcome of PST in all cases of partial remission and nearly 75% of cases of complete remission of primary tumours. According to the authors the use of microarray technology to identify genes that can predict response to chemotherapy could represent a powerful tool to identify patients for whom PST is the most appropriate, and would be the most successful form of treatment.
Why is this important ?
The significance of this work is its suggestion that breast cancer patients could find out whether they will respond positively to chemotherapy treatment by testing for the activity of certain genes. Researchers analysed the genes expressed in the tumours of eighty-three patients with primary breast cancer.
The researchers were able to predict which breast tumours would improve from chemotherapy in all cases of partial remission and nearly three quarters of the cases of complete remission based on the analysis of less than sixty genes present in the tumours. The authors of the study state that the ability to predict which patients will respond to chemotherapy, and which would not, would be a "powerful tool" in the treatment of breast cancer.
So, if it is not generally possible to predict who will benefit from chemotherapy at present, how are decisions made ?
Currently, decisions about whether to use chemotherapy as a breast cancer
treatment are based on factors such as patients' age and type and size
These factors do not provide sufficient information to tailor treatment to the individual patient.
Nearly all breast cancer patients receive standard chemotherapy treatment, despite the potential for a poor response to therapy, adverse side effects and excess healthcare costs.
According to the authors, "the identification of molecular markers predictive of patients' responsiveness to treatment is becoming a central focus of research".
The ability to predict a patient's response to chemotherapy for breast cancer would be of benefit to doctors and patients, shifting the focus away from a standard treatment for all patients and towards treatment based on predictions made from patients' genetic background.
The Journal of Translational Medicine