Development of Mouse-Tumor Model Using Prostate Cancer (PC3) Cell Line for High-Intensity Focused Ultrasound (HIFU) Ablation.

High-intensity focused ultrasound (HIFU) is a noninvasive modality that is gaining prominence for the localized treatment of malignant tumors. Most current HIFU research utilizes mouse tumor models, where selection of appropriate mouse breed is important for conducting thermal ablation experiments on tumors with consistency. In this study, three breeds (NOD/SCID GammaC -/- (NSG), NSG-SGM3 (NSGS), and Homozygote J:NU (Nude); n = 2 per group) originating from Jackson Laboratory were tested for identifying the breed that has sufficient size for conducting HIFU experiments. Tumors were developed using a human PC3 (CRL-1435) prostate cancer cell line and monitored over 5 to 7 weeks. The surface area and volume of the implanted tumors were determined by assuming the tumor having an ellipsoidal shape. At the end of the growth period, NSG mice exhibited 29% larger tumor surface area than NSGS and 58% larger than Nude mice. Similarly, NSG mice had a 55% larger tumor volume than NSGS mice and 100% larger than Nude mice. Therefore, this research established NSG mice as the superior mouse breed for the PC3 cell-induced tumor growth having established size within a reasonable timeline (5-7 weeks). Subsequently, the NSG model with a larger sample size (n = 48) was selected for HIFU ablation, and histopathological analysis revealed a significantly higher number of apoptotic cells in the HIFU-treated tumors compared to controls. This further confirmed the model's suitability for HIFU research. Tumor surface area and volume compared between the tested (n = 2) and selected (n = 48) groups were statistically insignificant (p = 0.78 for surface area and p = 0.60 for volume).