Charles M. Perou, PhD, Discusses Genomic Signatures and Dual HER2-Targeting in Breast Cancer

Charles M. Perou, PhD, professor of genetics, pathology & laboratory medicine, UNC Lineberger Comprehensive Cancer Center, discusses a trial (CALGB 40601) presented at the 2014 ASCO Annual Meeting that analyzed gene expression signatures in patients with HER2-positive breast cancer treated with weekly paclitaxel and trastuzumab with or without lapatinib.

This trial demonstrated that dual HER2-targeting improved pathologic complete response (pCR) by about 10%, though this was not statistically significant. Even so, Perou says there were biologically interesting trends observed in this analysis.

RNA analysis was performed to do gene expression profiling and evaluate genomic signatures as potential predictors of pCR and/or response to adding lapatinib to trastuzumab. The overall interesting finding here, Perou says, was that there were a number of different genomic signatures that were predictors of an increased likelihood of having a pCR. It was also discovered that the HER2-enriched subtype had high pCR rates (about 70%) in the paclitaxel/trastuzumab arm and almost 80% in the dual HER2-targeting arm. The pCR rate in all other subtypes was about 30-40%, Perou says.