Table 2.

Immune and Therapeutic Effects of Focused Ultrasound Tumor Thermal Ablation

Disease	Model	Treatment & FUS Parameters	Immunologic Effect	Therapeutic Effect
Melanoma	B16F10 (C57BL/6 mouse)	-Pressure: 5.42 MPa -Power: 12.5W, 4 s at each spot, Duty cycle: 75% -Separate study combined one 10-Gray (Gy) radiation dose post-HIFU treatment	-Increase in CD45+ cells, but no increase in T cells, signifying influx of other inflammatory cells in response to tissue damage	-Loss of primary tumor and tumor-bearing limb due to HIFU. Secondary tumors necessitated sacrifice of mice. (92)
Metastatic mammary carcinoma	NDL (FVB/n mouse)	-Ablation only or ablation + immunotherapy (αPD-1 and CpG every 3-4 days for 3 doses, followed by ablation and aPD-1 or CpG every 3-7 days for 4 doses) -Pressure: 3.1 MPa, Power: 5 W, Scan Speed: 1 rps (revolutions per second), CEM43 (cumulative equivalent minutes): >5000 for a temperature of >65°C	-Ablation only increased IFN-γ-producing CD4+ T cells and CD8+ T cells, decreased Treg cells. Lymphatic drainage was increased. -Immunotherapeutic priming reduced macrophages and MDSCs and increased number of IFN-γ-producing CD8+ T cells, M1 macrophage fractions, and PD-L1 expression on CD45+ producing CD8+ T cells.	-Immunotherapy primed with ablation caused 80% of mice with 1 tumor to completely respond by day 90. -60% of mice with 3 tumors completely responded compared to 25% with immunotherapy only. (59)
Melanoma, mammary adenocarcinoma & breast cancer	B16F10 (C57BL/6 mouse), NDL (FVB/n mouse) & MMTV-PyMT (transgenic mouse)	-B16F10 groups: ablation only and ablation + immunotherapy (CpG dose 4, 3, 2 and 0 days before ablation; anti-PD-1 dose 4 and 2 days before ablation) -NDL group: ablation + immunotherapy (AI) (CpG dose 10, 7, 3, and 0 days before ablation; αPD-1 dose 10 and 3 days before ablation and 4 days after ablation) -MMTV-PyMT group: ablation + immunotherapy (CpG dose 10, 7, 3, and 0 days before ablation; αPD-1 dose 10 and 3 days before ablation and 4 days after ablation) -Power: 5 and 10 W, Scan speed: 1 rps, CEM43: >5000 for a temperature of >65°C	-B16F10: Ablation only enhanced tumor fraction of immune cell expression of ovalbumin SIINFEKL peptide and number of infiltrating macrophages after 48 hours. AI-treatment induced type I IFN release and recruited CD169+ macrophages and dendritic cells in the tumor. -NDL: AI-treatment significantly increased CD3+, CD4+, CD8+ T-cells in contralateral tumors compared to all groups 1 week after treatment. AI increased number of unique CDR3 rearrangements and T-cell receptor overlap between tumors and blood. -MMTV-PyMT: AI-treatment significantly increased CD8+ T-cells in contralateral tumors compared to all groups 1 week after treatment.	-B16F10: Tumor volume 4 days after treatment was reduced by AI treatment in 4 of 5 mice. -NDL: AI tumor growth reduction greater than immunotherapy alone 1 week after treatment. 100% of AI-treated and 90% of AI-contralateral tumors reduced by 1 standard deviation compared to no treatment. -MMTV-PyMT: AI tumor growth reduction greater than immunotherapy alone. (60)
Melanoma	B16F10 (C57BL/6J mouse)	-Frequency: 9.3 MHz, Power: 4.5 W, 10 s at each spot, total exposure time 120 s	-HIFU suppressed miR-134 expression and activated co-stimulatory molecules CD86 and ICAM-1 expression in the tumor. -IFN-γ and TNF-α increased in the blood.	-HIFU decreased circulating B16F10 cells and pulmonary metastasis nodules -Tumor volume at day 31 was 2/3 less using HIFU compared to sham. (95)
Hepatocellular carcinoma	H22, (C57BL/6mouse)	-Frequency: 9.5 MHz, Power: 5 W, focal length: 8 mm, total exposure time: 220 s	-HIFU increased CD3+ and CD4+ levels in peripheral blood, increased CD4+/CD8+ ratio, and decreased CD8+ ratio compared to sham. TNF-α and IFN-γ secretion from splenic T cells was higher in HIFU than sham and control.	-Adoptive transfer of T-cells from HIFU-treated tumors into mice with H22 tumors prolonged the 60-day survival period. (96)