In discussing the findings of this study on genetic sequencing of breast cancer tissue, Fabrice
André, MD, PhD, of the Gustave Roussy Institute, in Villejuif, France, questioned whether all the genes that were found to be enriched in the relapsed samples were driving the relapse and whether any could be considered markers of recurrence.

Dr. André also indicated that research from his own laboratory does not substantiate the findings. Although Dr. Yates’ study identified 11 genes that were highly enriched in the relapsed tissue samples, his examination of 183 samples in SAFIR 01/02 found only 1 of these genes (ESR1) to be highly enriched.

Dr. André also wondered whether the late mutations that were identified are clinically relevant and whether they may explain the development of resistance to therapy, as has been seen in some other tumor types. He also questioned the mandate to re-biopsy, since “liquid biopsy” with circulating tumor cells and cell-free DNA are emerging as possible—and easier—alternatives.

Additional Comments

Also commenting on the study was Peter Naredi, MD, PhD, Professor of Surgery at Sahlgrenska University Hospital in Gothenburg, Sweden. Dr. Naredi, who served as the European Cancer Organization scientific co-chair of the 2015 European Cancer Congress, stated that the study provides important information for “the era of precision medicine.”

“This study underlines the fact that we should consider a recurrence of a cancer as a new event and carefully select the right treatment for the recurrent tumor as opposed to just relying on information from the first occurrence,” Dr. Naredi suggested.   ■

Disclosure: Dr. André has received research grants from Novartis, AstraZeneca, Lilly, Eisai, and has received honorarium from Celgene. Dr. Naredi reported no potential conflicts of interest.