Scientists at VCU Massey Cancer Center have discovered a biological process that allows breast tumor cells to develop resistance to standard treatment, a finding that could lead to more effective therapies for the disease.

The research published in Drug Resistance Updates reveals current drugs don’t completely eliminate the HER2 protein receptor, allowing tumor cells to partner with other proteins and continue growing.

The study suggests drugs targeting both HER2 and the related EGFR receptor may be needed to overcome resistance in HER2-positive breast cancers, which account for nearly 20% of cases.

“The efficacy of the standard of care is very limited,” said lead researcher Dr. Yuesheng Zhang, a professor at VCU. “Even patients who initially respond will very quickly develop resistance.”

The researchers tested a promising new drug in combination with an existing therapy. It achieved total remission in one resistant breast cancer model and reduced tumor growth by nearly 70% in others where the cancer had spread to the brain.

“This drug can actually cross the blood-brain barrier to attack the tumor,”

Dr. Zhang said. His team is in talks with the National Cancer Institute to potentially move the drug into clinical trials.

While encouraged by their drug’s performance, Dr. Zhang said the study’s key impact is revealing the underlying mechanism that must be targeted to improve outcomes for patients with this aggressive cancer.

“This paper will move the field forward because cancer scientists can develop other drugs to target this vulnerability,” he said. “Our agent is only one of those.”