Gene Expression Tests Helps Tailor Cancer Treatments

Breast cancers contain many different cell types with different patterns of gene expression which when tested for can help tailor cancer treatments to individual patients.

Breast carcinomas contain a variety of diverse cell types and an important result of this heterogeneity is that different biopsy specimens from a single breast cancer tumor can exhibit significant variability in genes expression.

Oncologists from the Maria Sklodowska-Curie Memorial Cancer Center (Warsaw, Poland) took a total of 78 different biopsies from 26 individual tumors to assess the degree of genomic variation, and its impact on a set of 32 different prognostic and predictive multigene signatures. The team performed gene expression profiling on their 78 samples using oligonucleotide microarrays.

Overall, they found that the gene expression profiles of the cores were variable, and in at least five patients, this heterogeneity was substantial. However, when they analyzed a number of multigene signatures selected from previous studies, this heterogeneity was considerably less significant. The gene sets differed in their variance between biopsies. 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 trials and patient tissues.

Michał Jarząb, MD, the senior author of the study said, “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. Our study confirms that it is possible to address tumor heterogeneity when carrying out routine diagnostic procedures in patients. Our results may help to introduce the better tailoring of preoperative treatment."

Angelo Di Leo, MD, PhD, from the Tuscan Cancer Institute (Florence, Italy) said, “The study is innovative because it is one of the first to address the question of intratumor heterogeneity. It means that not all the cells from the same tumor have the same characteristics, and if we want to have a clear picture of the tumor biology we should not limit the evaluation of tumor markers to one area of the tumor itself." The studies were presented at the Annual IMPAKT Breast Cancer Conference, held May 2–4, 2013, in Brussels (Belgium).

Related Links:
Maria Skłodowska-Curie Memorial Cancer Center
Tuscan Cancer Institute