Therapeutic Effects of Microbubbles Added to Combined High-Intensity Focused Ultrasound and Chemotherapy in a Pancreatic Cancer Xenograft Model

Local ablative therapies and the effect on antitumor immune responses in pancreatic cancer - A review

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease, projected to rank as the second most prevalent cause of cancer-related mortality by 2030. Despite significant progress in advances in surgical techniques and chemotherapy protocols, the overall survival (OS) remains to be less than 10 % for all stages combined. In recent years, local ablative techniques have been introduced and utilized as additional therapeutic approaches for locally advanced pancreatic cancer (LAPC), with promising results with respect to local tumor control and OS. In addition to successful cytoreduction, there is emerging evidence that local ablation induces antitumor immune activity that could prevent or even treat distant metastatic tumors. The enhancement of antitumor immune responses could potentially make ablative therapy a therapeutic option for the treatment of metastatic PDAC. In this review, we summarize current ablative techniques used in the management of LAPC and their impact on systemic immune responses.

Systemic and Local Strategies for Primary Prevention of Breast Cancer

One in eight women will develop breast cancer in the US. For women with moderate (15-20%) to average (12.5%) risk of breast cancer, there are few options available for risk reduction. For high-risk (>20%) women, such as BRCA mutation carriers, primary prevention strategies are limited to evidence-based surgical removal of breasts and/or ovaries and anti-estrogen treatment. Despite their effectiveness in risk reduction, not many high-risk individuals opt for surgical or hormonal interventions due to severe side effects and potentially life-changing outcomes as key deterrents. Thus, better communication about the benefits of existing strategies and the development of new strategies with minimal side effects are needed to offer women adequate risk-reducing interventions. We extensively review and discuss innovative investigational strategies for primary prevention. Most of these investigational strategies are at the pre-clinical stage, but some are already being evaluated in clinical trials and others are expected to lead to first-in-human clinical trials within 5 years. Likely, these strategies would be initially tested in high-risk individuals but may be applicable to lower-risk women, if shown to decrease risk at a similar rate to existing strategies, but with minimal side effects.

Combination of chemotherapy and focused ultrasound for the treatment of unresectable pancreatic cancer: a proof-of-concept study

OBJECTIVES

To investigate the safety and preliminary efficacy of the combined treatment of focused ultrasound (FUS) and chemotherapy (nab-paclitaxel plus gemcitabine, nPac/Gem) for patients with unresectable pancreatic cancer.

METHODS

Patients pathologically diagnosed with unresectable pancreatic cancer were included. Low (Isppa = 1.5 kW/cm²), intermediate (2.0 kW/cm²), and high (2.5 kW/cm²) FUS intensity treatment groups were predefined. A 1% duty cycle and the 3+3 scheme were used. Six combined treatments were performed, and adverse events were assessed. Changes in tumor size and tumor response, CA 19-9 level, and patient-reported outcomes at the immediate follow-up (F/U) and/or at the 3-month F/U and survival were evaluated.

RESULTS

Three participants were enrolled in each intensity group. No adverse device effect or dose-limiting toxicity occurred in any of the participants. Seven of the nine participants experienced a >15% tumor size decrease at the immediate F/U CT and at the 3-month F/U CT. The CA 19-9 level decreased in all of the participants at the immediate F/U. All participants in the intermediate-intensity treatment group showed a > 30% tumor size decrease, partial response, and a significant decrease in the CA 19-9 level at 3-month F/U and longer survival (p < 0.05).

CONCLUSION

FUS with an intensity of 1.5 to 2.5 kW/cm² was safe in the combined treatment of FUS and nPac/Gem. Considering the results of the change in tumor size, the change in CA 19-9 level, tumor response, and survival, these FUS parameters can be used for subsequent clinical trials.

KEY POINTS

• No adverse device effect or dose-limiting toxicity occurred in any of the participants when focused ultrasound with an intensity of 1.5-2.5 kW/cm² and a low duty cycle of 1% was combined with chemotherapy. • The intermediate-intensity group showed a >30% tumor size decrease, partial response, and a significant decrease in CA 19-9 in all of the participants at the 3-month follow-up and the longest survival. • Any focused ultrasound setting used in this study could be safe and optimal for subsequent clinical trials.

Ultrasound nanomedicine and materdicine

The conventional microbubble-based ultrasound biomedicine clinically plays a vital role in providing the dynamic detection of macro and microvasculature and disease theranostics. However, the intrinsic limitation of particle size severely decreases the treatment effectiveness due to their vascular transport characteristics, which promotes the development and application of multifunctional ultrasound-responsive nanomaterials. Herein, we put forward a research field of "ultrasound nanomedicine and materdicine", referring to the interdiscipline of ultrasound, nanobiotechnology and materials, which seeks to produce specific biological effects for addressing the challenges faced and dilemma of conventional ultrasound medicine. We comprehensively summarize the state-of-the-art scientific advances in the latest progress in constructing ultrasound-based platforms and ultrasound-activated sonosensitizers, ranging from the synthesis strategies, biological functions to ultrasound-triggered therapeutic applications. Ultimately, the unresolved challenges and clinical-translation potentials of ultrasound nanomedicine and materdicine are discussed and prospected in this evolving field.

Effect of acoustic cluster therapy (ACT®) combined with chemotherapy in a patient-derived xenograft mouse model of pancreatic cancer

Pancreatic ductal adenocarcinomas respond poorly to chemotherapy, in part due to the dense tumor stroma that hinders drug delivery. Ultrasound (US) in combination with microbubbles has previously shown promise as a means to improve drug delivery, and the therapeutic efficacy of ultrasound-mediated drug delivery is currently being evaluated in multiple clinical trials. However, most of these utilize echogenic contrast agents engineered for imaging, which might not be optimal compared to specialized formulations tailored for drug delivery. In this study, we evaluated the in vivo efficacy of phase-shifting microbubble-microdroplet clusters that, upon insonation, form bubbles in the size range of 20-30 μm. We developed a patient-derived xenograft model of pancreatic cancer implanted in mice that largely retained the stromal content of the originating tumor and compared tumor growth in mice given chemotherapeutics (nab-paclitaxel plus gemcitabine or liposomal irinotecan) with mice given the same chemotherapeutics in addition to ultrasound and acoustic cluster therapy. We found that acoustic cluster therapy significantly improved the effect of both chemotherapeutic regimens and resulted in 7.2 times higher odds of complete remission of the tumor compared to the chemotherapeutics alone.

Low-Intensity Focused Ultrasound Produces Immune Response in Pancreatic Cancer

Pancreatic adenocarcinoma is an aggressive malignancy with limited therapeutic treatments available and a 5-y survival less than 10%. Pancreatic cancers have been found to be immunogenically "cold" with a largely immunosuppressive tumor microenvironment. There is emerging evidence that focused ultrasound can induce changes in the tumor microenvironment and have a constructive impact on the effect of immunotherapy. However, the immune cells and timing involved in these effects remain unclear, which is essential to determining how to combine immunotherapy with ultrasound for treatment of pancreatic adenocarcinoma. We used low-intensity focused ultrasound and microbubbles (LoFU + MBs), which can mechanically disrupt cellular membranes and vascular endothelia, to treat subcutaneous pancreatic tumors in C57BL/6 mice. To evaluate the immune cell landscape and expression and/or localization of damage-associated molecular patterns (DAMPs) as a response to ultrasound, we performed flow cytometry and histology on tumors and draining lymph nodes 2 and 15 d post-treatment. We repeated this study on larger tumors and with multiple treatments to determine whether similar or greater effects could be achieved. Two days after treatment, draining lymph nodes exhibited a significant increase in activated antigen presenting cells, such as macrophages, as well as expansion of CD8+ T cells and CD4+ T cells. LoFU + MB treatment caused localized damage and facilitated the translocation of DAMP signals, as reflected by an increase in the cytoplasmic index for high-mobility-group box 1 (HMGB1) at 2 d. Tumors treated with LoFU + MBs exhibited a significant decrease in growth 15 d after treatment, indicating a tumor response that has the potential for additive effects. Our studies indicate that focused ultrasound treatments can cause tumoral damage and changes in macrophages and T cells 2 d post-treatment. The majority of these effects subsided after 15 d with only a single treatment, illustrating the need for additional treatment types and/or combination with immunotherapy. However, when larger tumors were treated, the effects seen at 2 d were diminished, even with an additional treatment. These results provide a working platform for further rational design of focused ultrasound and immunotherapy combinations in poorly immunogenic cancers.

High intensity focused ultrasound for the treatment of solid tumors: a pilot study in canine cancer patients

PURPOSE

To investigate the safety, feasibility, and outcomes of High-Intensity Focused Ultrasound (HIFU) for the treatment of solid tumors in a spontaneous canine cancer model.

METHODS

Dogs diagnosed with subcutaneous solid tumors were recruited, staged and pretreatment biopsies were obtained. A single HIFU treatment was delivered to result in partial tumor ablation using a commercially available HIFU unit. Tumors were resected 3-6 days post HIFU and samples obtained for histopathology and immunohistochemistry. Total RNA was isolated from paired pre and post treated FFPE tumor samples, and quantitative gene expression analysis was performed using the nCounter Canine IO Panel.

RESULTS

A total of 20 dogs diagnosed with solid tumors were recruited and treated in the study. Tumors treated included Soft Tissue Sarcoma (n = 15), Mast Cell Tumor (n = 3), Osteosarcoma (n = 1), and Thyroid Carcinoma (n = 1). HIFU was well tolerated with only 1 dog experiencing a clinically significant adverse event. Pathology confirmed the presence of complete tissue ablation at the HIFU targeted site and immunohistochemistry indicated immune cell infiltration at the treated/untreated tumor border. Quantitative gene expression analysis indicated that 28 genes associated with T-cell activation were differentially expressed post-HIFU.

CONCLUSIONS

HIFU appears to be safe and feasible for the treatment of subcutaneous canine solid tumors, resulting in ablation of the targeted tissue. HIFU induced immunostimulatory changes, highlighting the canine cancer patient as an attractive model for studying the effects of focal ablation therapies on the tumor microenvironment.

High-intensity focused ultrasound therapy for pancreatic cancer

Pancreatic cancer (PC) has one of the poorest prognoses among solid cancers, and its incidence has increased recently. Satisfactory outcomes are not achieved with current therapies; thus, novel treatments are urgently needed. High-intensity focused ultrasound (HIFU) is a novel therapy for ablating tissue from the outside of the body by focusing ultrasonic waves from multiple sources on the tumor. In this therapy, only the focal area is heated to 80-100 ºC, which causes coagulative necrosis of the tissue, with hardly any impact on the tissue outside the focal area. Although HIFU is a minimally invasive treatment and is expected to be useful, it is not yet generally known. Here, we discuss the usefulness of HIFU treatment for un-resectable advanced PC using the results of previous research, meta-analyses, and systematic reviews on its efficacy and safety. HIFU therapy for un-resectable PC is useful for its anti-tumor effect and pain relief, and is expected to prolong survival time and improve quality of life. Although HIFU for PC has several limitations and further study is needed, this technique can be safely performed on un-resectable advanced PC. In future, HIFU could be utilized as a minimally invasive treatment strategy for PC patients with a poor prognosis.

Delivery of anti-cancer drugs using microbubble-assisted ultrasound in digestive oncology: From preclinical to clinical studies

INTRODUCTION

The combination of microbubbles (MBs) and ultrasound (US) is an emerging method for the noninvasive and targeted enhancement of intratumor chemotherapeutic uptake. This method showed an increased local drug extravasation in tumor tissue while reducing the systemic adverse effects in various tumor models.

AREA COVERED

We focused on preclinical and clinical studies investigating the therapeutic efficacy and safety of this technology for the treatment of colorectal, pancreatic and liver cancers. We discussed the limitations of the current investigations and future perspectives.

EXPERT OPINION

The therapeutic efficacy and the safety of delivery of standard chemotherapy regimen using MB-assisted US have been mainly demonstrated in subcutaneous models of digestive cancers. Although some clinical trials on pancreatic ductal carcinoma and hepatic metastases from various digestive cancers have shown promising results, successful evaluation of this method in terms of US settings, chemotherapeutic schemes and MBs-related parameters will need to be addressed in more relevant preclinical models of digestive cancers, in small and large animals before fully and successfully translating this technology for clinic use. Ultimately, a clear evidence of the correlation between the enhanced intratumoral concentrations of therapeutics and the increased therapeutic response of tumors have to be provided in clinical trials.

Novel Therapeutic Method for Unresectable Pancreatic Cancer-The Impact of the Long-Term Research in Therapeutic Effect of High-Intensity Focused Ultrasound (HIFU) Therapy

High-intensity focused ultrasound (HIFU) is a novel advanced therapy for unresectable pancreatic cancer (PC). HIFU therapy with chemotherapy is being promoted as a novel method to control local advancement by tumor ablation. We evaluated the therapeutic effects of HIFU therapy in locally advanced and metastatic PC. PC patients were treated with HIFU as an optional local therapy and systemic chemotherapy. The FEP-BY02 (Yuande Bio-Medical Engineering) HIFU device was used under ultrasound guidance. Of 176 PC patients, 89 cases were Stage III and 87 were Stage IV. The rate of complete tumor ablation was 90.3%, while that of symptom relief was 66.7%. The effectiveness on the primary lesions were as follows: complete response (CR): n = 0, partial response (PR): n = 21, stable disease (SD): n = 106, and progressive disease (PD): n = 49; the primary disease control rate was 72.2%. Eight patients underwent surgery. The median survival time (MST) after diagnosis for HIFU with chemotherapy compared to chemotherapy alone (100 patients in our hospital) was 648 vs. 288 days (p < 0.001). Compared with chemotherapy alone, the combination of HIFU therapy and chemotherapy demonstrated significant prolongation of prognosis. This study suggests that HIFU therapy has the potential to be a novel combination therapy for unresectable PC.

Phase-changeable nanoparticle-mediated energy conversion promotes highly efficient high-intensity focused ultrasound ablation

This review describes how phase-changeable nanoparticles enable highly efficient high-intensity focused ultrasound ablation (HIFU). HIFU is effective in the clinical treatment of solid malignant tumors. However, it has intrinsic disadvantages for treating some deep lesions, such as damage to surrounding normal tissues. When phase-changeable nanoparticles are used in HIFU treatment, they could serve as good synergistic agents because they are transported in the blood and permeated and accumulated effectively in tissues. HIFU's thermal effects can trigger nanoparticles to undergo a special phase transition, thus enhancing HIFU ablation efficiency. Nanoparticles can also carry anticancer agents and release them in the targeted area to achieve chemo-synergistic therapy response. Although the formation of nanoparticles is complicated and HIFU applications are still in an early stage, the potential for their use in synergy with HIFU treatment shows promising results.

Synergistic Effects of Pulsed Focused Ultrasound and a Doxorubicin-Loaded Microparticle-Microbubble Complex in a Pancreatic Cancer Xenograft Mouse Model

The synergistic effects of a doxorubicin (Dox)-loaded microparticle-microbubble complex (DMMC) and focused ultrasound (FUS) with a short duty cycle (5%) were evaluated in a pancreatic cancer xenograft model established by inoculating immunodeficient mice with CFPAC-1 cells. The efficacy of the DMMC with FUS (study 1), the effect of conjugating the particles as opposed to mixing them (study 2) and the levels of tumor apoptosis and intracellular Dox (study 3) were evaluated. The DMMC with FUS exhibited the lowest tumor growth rate (30.8 mm³/wk) and the highest intracellular Dox uptake (8.8%) and tumor cell apoptosis rate (58.7%) among all treatments. DMMC had a significantly lower growth rate than the mixture of Dox-loaded microparticles and microbubbles (44.2 mm³/wk, p < 0.01) when they were combined with FUS. In conclusion, DMMC with short-duty-cycle FUS holds promise for tumor growth suppression, which may be attributed to high intracellular Dox uptake.

In Vivo Flow Cytometric Evaluation of Circulating Metastatic Pancreatic Tumor Cells after High-Intensity Focused Ultrasound Therapy

We examined our hypothesis that high-intensity focused ultrasound (HIFU) treatment of pancreatic ductal adenocarcinoma (PDAC) in nude mice models may lead to an increased occurrence of hematogenous metastasis. The human PDAC cell line BxPC-3 transfected with mCherry was implanted into nude mice to establish orthotopic and subcutaneous xenograft (OX and SX) tumor models. Mice were exposed to HIFU when tumor sizes reached approximately 200-300 mm³ . The OX and SX tumor models were monitored continuously for tumor growth characteristics and hematogenous metastasis using in vivo flow cytometric (IVFC) detection of circulating tumor cells (CTCs) from the pancreas. We chose an appropriate mouse model to further examine whether or not HIFU increases the potential risk of hematogenous metastasis, using IVFC detection. Our results showed that the CTC number was greater in the OX model than in the SX model. The CTC number in the OX model increased gradually over time, whereas the CTC number in the SX model remained low. Therefore, the OX model was better for studying tumor metastasis by IVFC detection. We found significantly decreased CTC numbers and tumor volume after HIFU ablation. Our results showed the applicability of the PDAC OX tumor model for studying the occurrence of tumor metastasis due to the generation of CTCs. HIFU ablation substantially restricted PDAC hematogenous metastasis and provided effective tumor control locally. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals Inc., on behalf of International Society for Advancement of Cytometry.

Magnetic resonance imaging biomarkers for pulsed focused ultrasound treatment of pancreatic ductal adenocarcinoma

BACKGROUND

The robust fibroinflammatory stroma characteristic of pancreatic ductal adenocarcinoma (PDA) impedes effective drug delivery. Pulsed focused ultrasound (pFUS) can disrupt this stroma and has improved survival in an early clinical trial. Non-invasive methods to characterize pFUS treatment effects are desirable for advancement of this promising treatment modality in larger clinical trials.

AIM

To identify promising, non-invasive pre-clinical imaging methods to characterize acute pFUS treatment effects for in vivo models of PDA.

METHODS

We utilized quantitative magnetic resonance imaging methods at 14 tesla in three mouse models of PDA (subcutaneous, orthotopic and transgenic - Kras^LSL-G12D/+, Trp53^LSL-R172H/+, Cre or “KPC”) to assess immediate tumor response to pFUS treatment (VIFU 2000 Alpinion Medical Systems; 475 W peak electric power, 1 ms pulse duration, 1 Hz, duty cycle 0.1%) vs sham therapy, and correlated our results with histochemical data. These pFUS treatment parameters were previously shown to enhance tumor permeability to chemotherapeutics. T1 and T2 relaxation maps, high (126, 180, 234, 340, 549) vs low (7, 47, 81) b-value apparent diffusion coefficient (ADC) maps, magnetization transfer ratio (MTR) maps, and chemical exchange saturation transfer (CEST) maps for the amide proton spectrum (3.5 parts per million or “ppm”) and the glycosaminoglycan spectrum (0.5-1.5 ppm) were generated and analyzed pre-treatment, and immediately post-treatment, using ImageJ. Animals were sacrificed immediately following post-treatment imaging. The whole-tumor was selected as the region of interest for data analysis and subsequent statistical analysis. T-tests and Pearson correlation were used for statistical inference.

RESULTS

Mean high-b value ADC measurements increased significantly with pFUS treatment for all models. Mean glycosaminoglycan CEST and T2 measurements decreased significantly post-treatment for the KPC group. Mean MTR and amide CEST values increased significantly for the KPC group. Hyaluronic acid focal intensities in the treated regions were significantly lower following pFUS treatment for all animal models. The magnetic resonance imaging changes observed acutely following pFUS therapy likely reflect: (1) Sequelae of variable degrees of microcapillary hemorrhage (T1, MTR and amide CEST); (2) Lower PDA glycosaminoglycan content and associated water content (glycosaminoglycan CEST, T2 and hyaluronic acid focal intensity); and (3) Improved tumor diffusivity (ADC) post pFUS treatment.

CONCLUSION

T2, glycosaminoglycan CEST, and ADC maps may provide reliable quantitation of acute pFUS treatment effects for patients with PDA.

High-intensity focused ultrasound enhances the effect of bufalin by inducing apoptosis in pancreatic cancer cells

Purpose

High-intensity focused ultrasound (HIFU) has the potential to be an effective therapeutic strategy for pancreatic cancer (PC). However, owing to the high malignancy and poor prognosis of PC, the use of HIFU therapy alone is not sufficient to impair the progression of PC. Bufalin, a compound extracted from traditional medicine, is known to inhibit the growth and progression of PC cells. However, the effect of the combination therapy of HIFU plus bufalin (HIFU+bufalin) is still uncertain.

Materials and methods

A colony formation assay and flow cytometry were performed to measure the growth and induction of apoptosis in PC cells. Western blotting was used to explore the potential mechanism of HIFU and bufalin therapy. The in vivo efficacy of HIFU+bufalin was tested in a MiaPaCa₂ xenograft model.

Results

Bufalin inhibited the growth of PC cells more obviously compared to HIFU. Combining bufalin with HIFU further decreased the growth of MiaPaCa₂ cells compared with single therapy in vitro. Flow cytometry results showed that the percentage of surviving MiaPaCa₂ cells in the bufalin-treated group and the HIFU-treated group was approximately three-fold and two-fold higher than in the HIFU+bufalin-treated group. Contrasting results were found in Panc-1 cells. Biochemical analysis revealed that HIFU+bufalin treatment elevated PARP expression and increased caspase-8 activation in MiaPaCa₂ and Panc-1 cells. HIFU+bufalin significantly reduced the growth of MiaPaCa₂ tumors compared with HIFU or bufalin treatment alone. HIFU+bufalin treatment decreased Ki67 staining and increased activated caspase-3 and caspase 8 staining, when compared with HIFU or bufalin treatment alone in mouse tumors.

Conclusion

HIFU enhanced the effect of bufailn by inducing apoptosis in PC cells. A combination of HIFU and bufalin may be employed as an alternative therapeutic strategy for PC.

A portable high-intensity focused ultrasound system for the pancreas with 3D electronic steering: a preclinical study in a swine model

PURPOSE

The aim of this animal study was to evaluate the safety and feasibility of a portable, ultrasonography-guided, high-intensity focused ultrasound (USg-HIFU) system to treat the pancreas.

METHODS

Eight swine were included. Using a portable HIFU device (ALPIUS 900, Alpinion Medical Systems), ablations were performed on the pancreas in vivo. Different acoustic intensities were applied (1.7 kW/cm2 or 1.5 kW/cm2 , n=2 [group A for a pilot study]; 1.5 kW/ cm2 , n=3 [group B]; and 1.2 kW/cm2 , n=3 [group C]). Magnetic resonance imaging (MRI) was performed immediately (group A) or 7 days (groups B and C) after HIFU treatment. In groups B and C, serum amylase and lipase levels were measured on days 0 and 7, and performance status was observed every day. Necropsy was performed on days 0 (group A) or 7 (groups B and C) to assess the presence of unintended injuries and to obtain pancreatic and peripancreatic tissue for histological analysis.

RESULTS

Ablation was noted in the pancreas in all swine on MRI, and all pathologic specimens showed coagulation necrosis in the treated area. The mean ablation areas on MRI were 85.3±38.1 mm2, 90.7±21.2 mm2, and 54.4±30.6 mm2 in groups A, B, and C, respectively (P>0.05). No animals showed evidence of complications, except for one case of a pseudocyst in group B.

CONCLUSION

This study showed that pancreas ablation using a portable USg-HIFU system may be safe and feasible, and that coagulation necrosis of the pancreas was successfully achieved with a range of acoustic intensities.

Focused ultrasound: tumour ablation and its potential to enhance immunological therapy to cancer

Various kinds of image-guided techniques have been successfully applied in the last years for the treatment of tumours, as alternative to surgical resection. High intensity focused ultrasound (HIFU) is a novel, totally non-invasive, image-guided technique that allows for achieving tissue destruction with the application of focused ultrasound at high intensity. This technique has been successfully applied for the treatment of a large variety of diseases, including oncological and non-oncological diseases. One of the most fascinating aspects of image-guided ablations, and particularly of HIFU, is the reported possibility of determining a sort of stimulation of the immune system, with an unexpected "systemic" response to treatments designed to be "local". In the present article the mechanisms of action of HIFU are described, and the main clinical applications of this technique are reported, with a particular focus on the immune-stimulation process that might originate from tumour ablations.

Focused ultrasound for immuno-adjuvant treatment of pancreatic cancer: An emerging clinical paradigm in the era of personalized oncotherapy

Current clinical treatment regimens, including many emergent immune strategies (e.g., checkpoint inhibitors) have done little to affect the devastating course of pancreatic ductal adenocarcinoma (PDA). Clinical trials for PDA often employ multi-modal treatment, and have started to incorporate stromal-targeted therapies, which have shown promising results in early reports. Focused ultrasound (FUS) is one such therapy that is uniquely equipped to address local and systemic limitations of conventional cancer therapies as well as emergent immune therapies for PDA. FUS methods can non-invasively generate mechanical and/or thermal effects that capitalize on the unique oncogenomic/proteomic signature of a tumor. Potential benefits of FUS therapy for PDA include: (1) emulsification of targeted tumor into undenatured antigens in situ, increasing dendritic cell maturation, and increasing intra-tumoral CD8+/ T regulatory cell ratio and CD8+ T cell activity; (2) reduction in intra-tumoral hypoxic stress; (3) modulation of tumor cell membrane protein localization to enhance immunogenicity; (4) modulation of the local cytokine milieu toward a Th1-type inflammatory profile; (5) up-regulation of local chemoattractants; (6) remodeling the tumor stroma; (7) localized delivery of exogenously packaged immune-stimulating antigens, genes and therapeutic drugs. While not all of these results have been studied in experimental PDA models to date, the principles garnered from other solid tumor and disease models have direct relevance to the design of optimal FUS protocols for PDA. In this review, we address the pertinent limitations in current and emergent immune therapies that can be improved with FUS therapy for PDA.