However, when they analysed a number of multi-gene signatures selected from previous studies, this heterogeneity was considerably less significant.
The gene sets differed in their variance between biopsies, the authors found. The most pronounced heterogeneity was observed in immune response-related genes, while the least heterogeneous were the classifiers based on genes selected by advanced bioinformatical methods from both cell culture experiments and patient tissues.
"Overall, the heterogeneity among the potentially predictive genes was small enough and we conclude that this factor should not prohibit their effective use in clinical practice," Dr Jarząb says.
"Our study confirms that it is possible to address tumour heterogeneity when carrying out routine diagnostic procedures in patients. Our results may help to introduce the better tailoring of preoperative treatment."
Commenting on the results, Dr. Angelo Di Leo, Head of the Sandro Pitigliani Medical Oncology Unit and Chair of the Oncology Department at the Hospital of Prato, Istituto Toscano Tumori, Italy, said: "If other studies report similar results to this one, then it could become common practice to evaluate prognostic or predictive breast cancer markers from more than one primary tumour area."
"The study is innovative because it is one of the first to address the question of intratumour heterogeneity. It means that not all the cells from the same tumour have the same characteristics, and if we want to have a clear picture of the tumour biology we should not limit the evaluation of tumour markers to one area of the tumour itself," Dr. Di Leo said.
|Contact: Vanessa Pavinato|
European Society for Medical Oncology