A phase 2 clinical trial has found that an mRNA-based vaccine may help the immune system target HER2-positive breast cancer, one of the more aggressive forms of the disease. Researchers reported encouraging immune responses in about 65% of participants, adding to growing interest in mRNA technology beyond infectious disease.

The study is still early-stage and does not prove the vaccine can improve survival or prevent recurrence. Scientists involved in the research said the results justify larger and longer trials to determine whether the approach can deliver meaningful clinical benefit for patients.

HER2-positive breast cancer accounts for a significant share of breast cancer cases and has historically required intensive treatment. If further testing confirms the findings, an mRNA vaccine strategy could become part of a broader effort to make cancer treatment more precise and less toxic.

For now, the trial offers a cautious but notable sign that mRNA platforms may have a role in oncology. Researchers say the next step is to measure whether the immune response observed in this study translates into real-world outcomes for patients.