HIFU induces reprogramming of the tumor immune microenvironment in a pancreatic cancer mouse model.

This study evaluates the effects of different high-intensity focused ultrasound irradiation (HIFU) methods on local tumor suppression and systemic antitumor effects, including the abscopal effect, in a mouse model of pancreatic cancer. To ascertain the efficacy of the treatment, pancreatic cancer cells were injected into the thighs of mice and HIFU was applied on one side using continuous waves or trigger pulse waves. Then, tumor volume, tissue changes, and immune marker levels were analyzed. Both the irradiation methods suppressed tumor growth, with the trigger pulse wave showing stronger effects and the difference being significant. Tumor suppression was also observed on the non-irradiated side, suggesting an abscopal effect. These effects vary depending on the irradiation method used. We conclude that HIFU induces both local tumor suppression and a systemic immune response, suggesting its potential for combination with immunotherapy for the treatment of pancreatic cancer.