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Purpose@#A near-infrared (NIR) fluorescence imaging is a promising tool for cancer-specific image guided surgery. Human epidermal receptor 2 (HER2) is one of the candidate markers for gastric cancer. In this study, we aimed to synthesize HER2-specific NIR fluorescence probes and evaluate their applicability in cancer-specific image-guided surgeries using an animal model. @*Materials and Methods@#An NIR dye emitting light at 800 nm (IRDye800CW; Li-COR) was conjugated to trastuzumab and an HER2-specific affibody using a click mechanism. HER2 affinity was assessed using surface plasmon resonance. Gastric cancer cell lines (NCI-N87 and SNU-601) were subcutaneously implanted into female BALB/c nu (6–8 weeks old) mice.After intravenous injection of the probes, biodistribution and fluorescence signal intensity were measured using Lumina II (Perkin Elmer) and a laparoscopic NIR camera (InTheSmart). @*Results@#Trastuzumab-IRDye800CW exhibited high affinity for HER2 (KD =2.093(3) pM).Fluorescence signals in the liver and spleen were the highest at 24 hours post injection, while the signal in HER2-positive tumor cells increased until 72 hours, as assessed using the Lumina II system. The signal corresponding to the tumor was visually identified and clearly differentiated from the liver after 72 hours using a laparoscopic NIR camera. AffibodyIRDye800CW also exhibited high affinity for HER2 (KD =4.71 nM); however, the signal was not identified in the tumor, probably owing to rapid renal clearance. @*Conclusions@#Trastuzumab-IRDye800CW may be used as a potential NIR probe that can be injected 2–3 days before surgery to obtain high HER2-specific signal and contrast. Affibodybased NIR probes may require modifications to enhance mobilization to the tumor site.
ABSTRACT
PURPOSE: The utility of 18-fluordesoxyglucose positron emission tomography ([¹⁸F]-FDG-PET) combined with computer tomography or magnetic resonance imaging (MRI) in gastric cancer remains controversial and a rationale for patient selection is desired. This study aims to establish a preclinical patient-derived xenograft (PDX) based [¹⁸F]-FDG-PET/MRI protocol for gastric cancer and compare different PDX models regarding tumor growth and FDG uptake.MATERIALS AND METHODS: Female BALB/c nu/nu mice were implanted orthotopically and subcutaneously with gastric cancer PDX. [¹⁸F]-FDG-PET/MRI scanning protocol evaluation included different tumor sizes, FDG doses, scanning intervals, and organ-specific uptake. FDG avidity of similar PDX cases were compared between ortho- and heterotopic tumor implantation methods. Microscopic and immunohistochemical investigations were performed to confirm tumor growth and correlate the glycolysis markers glucose transporter 1 (GLUT1) and hexokinase 2 (HK2) with FDG uptake.RESULTS: Organ-specific uptake analysis showed specific FDG avidity of the tumor tissue. Standard scanning protocol was determined to include 150 μCi FDG injection dose and scanning after one hour. Comparison of heterotopic and orthotopic implanted mice revealed a long growth interval for orthotopic models with a high uptake in similar PDX tissues. The H-score of GLUT1 and HK2 expression in tumor cells correlated with the measured maximal standardized uptake value values (GLUT1: Pearson r=0.743, P=0.009; HK2: Pearson r=0.605, P=0.049).CONCLUSIONS: This preclinical gastric cancer PDX based [¹⁸F]-FDG-PET/MRI protocol reveals tumor specific FDG uptake and shows correlation to glucose metabolic proteins. Our findings provide a PET/MRI PDX model that can be applicable for translational gastric cancer research.
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The incidence of esophagogastric junction (EGJ) cancer has been significantly increasing in Western countries. Appropriate planning for surgical therapy requires a reliable classification of EGJ cancers with respect to their exact location. Clinically, the most accepted classification of EGJ cancers is “adenocarcinoma of the EGJ” (AEG or “Siewert”), which divides tumor center localization into AEG type I (distal esophagus), AEG type II (“true junction”), and AEG type III (subcardial stomach). Treatment strategies in western countries routinely employ perioperative chemotherapy or neoadjuvant chemoradiation for cases of locally advanced cancers. The standard surgical treatment strategies are esophagectomy for AEG type I and gastrectomy for AEG type III cancers. For “true junctional cancers,” i.e., AEG type II, whether the extension of resection in the oral or aboral direction represents the most effective surgical therapy remains debatable. This article reviews the history of surgical EGJ cancer treatment and current surgical strategies from a Western perspective.
Subject(s)
Classification , Drug Therapy , Esophagectomy , Esophagogastric Junction , Gastrectomy , IncidenceABSTRACT
Esophagogastric junction (EGJ) cancer is a solid tumor entity with rapidly increasing incidence in the Western countries. Given the high proportion of advanced cancers in the West, treatment strategies routinely employed include surgery and chemotherapy perioperatively, and chemoradiation in neoadjuvant settings. Neoadjuvant chemoradiation and perioperative chemotherapy are mostly performed in esophageal cancer that extends to the EGJ and gastric as well as EGJ cancers, respectively. Recent trials have tried to combine both strategies in a perioperative context, which might have beneficial outcomes, especially in patients with EGJ cancer. However, it is difficult to recruit patients for trials, exclusively for EGJ cancers; therefore, the results have to be carefully reviewed before establishing a standard protocol. Trastuzumab was the first drug for targeted therapy that was positively evaluated for this tumor entity, and there are several ongoing trials investigating more targeted drugs in order to customize effective therapies based on tissue characteristics. The current study reviews the multimodal treatment concept for EGJ cancers in the West and summarizes the latest reports.