title: High-Frequency Ultrasound-Guided Injection for the Generation of a Novel Orthotopic Mouse Model of Human Thyroid Carcinoma.
abstract: BACKGROUND
  Thyroid carcinoma is the most common endocrine malignancy and has an increasing incidence. High-frequency ultrasound (HFUS) has a spatial resolution of 30 μm, which is a property that has been exploited for thyroid visualization and analysis in mice. The aim of this study was to generate a novel orthotopic mouse model of human follicular thyroid carcinoma (FTC) using an HFUS-guided injection system.
  
  
  METHODS
  Twenty Balb/C nude mice were injected in the right lobe of the thyroid with 2 × 10(6) FTC-133 cells using the microinjection HFUS-guided system, and 20 mice, used as a control, underwent surgical orthotopic implantation of 2 × 10(6) FTC-133 cells in the right lobe of the thyroid. All mice underwent HFUS imaging two weeks after cell injection; HFUS examinations and tumor volume (TV) measurements were repeated weekly. Micro-computed tomography was performed at different time points to determine whether lung metastasis had occurred. TVs were compared between the two models (surgical vs. HFUS-guided) using the Mann-Whitney U-test, and the Mantel-Cox log-rank test was applied to evaluate the death hazard. Hematoxylin and eosin analysis of formalin-fixed, paraffin-embedded mouse tissue was performed to validate the in vivo imaging results.
  
  
  RESULTS
  Of the HFUS-guided injected mice, 9/18 survived up to 40 days after the injection of tumor cells. Mice injected surgically had 100% mortality at day 29. Of 38 mice, 29 (14/18 HFUS, 15/20 surgical) showed metastasis in the salivary glands and lymph nodes, and 13 (10/18 HFUS, 3/20 surgical) also showed metastasis in the lungs, which was confirmed by histological analysis. In the surgical group, there was an evident, frequent (12/20 mice) involvement of the contralateral lobe of the thyroid, whereas this feature was only detected in 1/18 mice in the HFUS group. Statistical analysis showed the same pattern of growth in the two groups, and a significant hazard in the mice in the surgical group (p = 0.03).
  
  
  CONCLUSIONS
  This study demonstrated the technical feasibility of an HFUS-guided orthotopic mouse model of FTC. The HFUS-guided orthotopic model is easily reproducible and allows prolonged monitoring of the disease because the animals showed an increased survival rate.
authors: 1 Department of Advanced Biomedical Science, University of Naples Federico II , Naples, Italy .|2 CEINGE Biotecnologie Avanzate , Naples, Italy .|3 Institute of Biostructures and Bioimaging , CNR, Naples, Italy .
authors: Adelaide
authors: A
authors: Greco
authors: 1 Department of Advanced Biomedical Science, University of Naples Federico II , Naples, Italy .|2 CEINGE Biotecnologie Avanzate , Naples, Italy .
authors: Sandra
authors: S
authors: Albanese
authors: 4 IRCCS SDN , Naples, Italy .
authors: Luigi
authors: L
authors: Auletta
authors: 4 IRCCS SDN , Naples, Italy .
authors: Peppino
authors: P
authors: Mirabelli
authors: 3 Institute of Biostructures and Bioimaging , CNR, Naples, Italy .
authors: Antonella
authors: A
authors: Zannetti
authors: 5 National Cancer Institute , "Fondazione G. Pascale"-IRCCS, Naples, Italy .
authors: Crescenzo
authors: C
authors: D'Alterio
authors: 4 IRCCS SDN , Naples, Italy .
authors: Gennaro
authors: G
authors: Di Maro
authors: 4 IRCCS SDN , Naples, Italy .
authors: Francesca Maria
authors: FM
authors: Orlandella
authors: 2 CEINGE Biotecnologie Avanzate , Naples, Italy .|4 IRCCS SDN , Naples, Italy .|6 Department of Motor Science and Wellness, Università Parthenope , Naples, Italy .
authors: Giuliana
authors: G
authors: Salvatore
authors: 4 IRCCS SDN , Naples, Italy .|6 Department of Motor Science and Wellness, Università Parthenope , Naples, Italy .
authors: Andrea
authors: A
authors: Soricelli
authors: 4 IRCCS SDN , Naples, Italy .
authors: Marco
authors: M
authors: Salvatore
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging*; D000818:Animals; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D015994:Incidence; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D016016:Proportional Hazards Models; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*; D055114:X-Ray Microtomography