Potential use of high-resolution T2-weighted MRI with histopathologic findings in staging esophageal cancer

Background

Magnetic resonance imaging (MRI) has shown promising capabilities in diagnosing local esophageal carcinoma. This study investigated the clinical value of high resolution (HR; small field of view and continuous thin section) axial T2-weighted MRI (HR-T2WI) as a noninvasive method for esophageal carcinoma tumor staging (T staging).

Methods

Forty-two patients with biopsy-proven esophageal cancer were investigated using HR-T2WI. The discrepancies between the esophageal wall layers and tumor tissue were assessed for MRI T staging using a visual MRI signal intensity scale (low, intermediate, and high intensities). The computed tomography (CT) and MRI T staging was compared with whole-mount histopathological sections in all patients who underwent resection.

Results

HR-T2WI provided a thorough view of the esophageal wall and the tumor's anatomic layers. Of the 42 patients with histological tumors (HTs), there were 6 cases with tumors classified as HT-1a, 5 cases with HT-1b, 14 cases with HT-2, and 17 cases with HT-3/4, and their MRI T stages were 5 MRI-T1a, 6 MRI-T1b, 14 MRI-T2, and 17 MRI-T3/4, respectively. After analyzing the imaging presentation at different HT staginess, we found that HR-T2WI enabled a more accurate classification than was possible with CT. The difference in accuracy between CT and T2WI was statistically significant (P<0.05) in the entire sample and in HT_1-2 tumors and HT_3-4 tumors.

Conclusions

HR-T2WI clearly identified normal esophageal wall layers; it had high diagnostic accuracy when evaluating tumor invasion and in MRI-T staging for esophageal carcinoma. This study established staging criteria of esophageal carcinoma using HR-T2WI and indicated that this approach could be used as a supplemental noninvasive method for the local T staging of esophageal carcinoma.

miR-34a inhibits pancreatic cancer progression through Snail1-mediated epithelial-mesenchymal transition and the Notch signaling pathway

Epithelial–mesenchymal transition (EMT) and Notch signaling are important for the growth and invasion of pancreatic cancer, which is a leading cause of cancer-related deaths worldwide. miR-34a has been shown to play pivotal roles in the progression of several types of cancer. However, little is known about the regulatory mechanisms of miR-34a in pancreatic cancer processes. The aim of this study was to determine whether miR-34a has negative effects on pancreatic cancer and whether these effects are related to EMT and Notch signaling. In vitro, we demonstrated that miR-34a inhibited, while miR-34a inhibitors enhanced, migration and invasion of pancreatic cancer cell lines (PANC-1 and SW-1990).These effects were reversed by Snail1 overexpression or Snail1 shRNA. Furthermore, the anti-apoptotic effects of the miR-34a inhibitors in pancreatic cancer cells were abrogated by Notch1 shRNA. Luciferase reporter assays revealed that the Snail1 and Notch1 genes were direct targets of miR-34a. In vivo, we also demonstrated that miR-34a inhibited pancreatic cancer growth by decreasing Snail1 and Notch1 expression. Therefore, our results indicate that miR-34a inhibits pancreatic cancer progression by post-transcriptionally regulating Snail1 and Notch1 expression.

An "imaging-biopsy" strategy for colorectal tumor reconfirmation by multipurpose paramagnetic quantum dots

Glucose transporter1 (Glut1) plays important roles in treatment of colorectal cancer (CRC) involving early-stage diagnosis, subtype, TNM stage, and therapeutic schedule. Currently, in situ marking and tracking of the tumor biomarkers via clinical imaging remains great challenges in early stage CRC diagnosis. In this study, we have developed a unique cell-targeted, paramagnetic-fluorescent double-signal molecular nanoprobe for CRC in vivo magnetic resonance imaging (MRI) diagnosis and subsequent biopsy. The unique molecular nanoprobe is composed of a fluorescent quantum dot (QD) core; a coating layer of paramagnetic DTPA-Gd coupled BSA ((Gd)DTPA∙BSA), and a surface targeting moiety of anti-Glut1 polyclonal antibody. The engineered (Gd)DTPA∙BSA@QDs-PcAb is 35 nm in diameter and colloidally stable under both basic and acidic conditions. It exhibits strong fluorescent intensities and high relaxivity (r1 and r2: 16.561 and 27.702 s(-1) per mM of Gd(3+)). Distribution and expression of Glut1 of CRC cells are investigated by in vitro cellular confocal fluorescent imaging and MR scanning upon treating with the (Gd)DTPA∙BSA@QDs-PcAb nanoprobes. In vivo MRI shows real-time imaging of CRC tumor on nude mice after intravenously injection of the (Gd)DTPA∙BSA@QDs-PcAb nanoprobes. Ex vivo biopsy is subsequently conducted for expression of Glut1 on tumor tissues. These nanoprobes are found biocompatible in vitro and in vivo. (Gd)DTPA∙BSA@QDs-PcAb targeted nanoprobe is shown to be a promising agent for CRC cancer in vivo MRI diagnosis and ex vivo biopsy analysis. The "imaging-biopsy" is a viable strategy for tumor reconfirmation with improved diagnostic accuracy and biopsy in personalized treatment.

Emergency transcatheter arterial embolization for patients with acute massive duodenal ulcer hemorrhage

AIM: To evaluate the efficacy and safety of emergency transcatheter arterial embolization (ETAE) for patients with acute massive duodenal ulcer hemorrhage.

METHODS: Twenty-nine consecutive patients with acute massive bleeding of duodenal ulcer were admitted to our hospital from 2006 to 2011. Superselective angiography of the celiac and gastroduodenal arteries was performed to find out the bleeding sites before ETAE, then, embolotherapy was done with gelatin sponge particles or microstrips via a 5 French angiographic catheter or 3 French microcatheter. After ETAE, further superior mesenteric arteriography was undertaken in case collateral circulation supplied areas of the duodenal ulcer. Technical and clinical success rates were analyzed. Changes in the mucous membrane were observed using endoscopy following ETAE.

RESULTS: Angiography showed active bleeding with extravasation of contrast medium in seven cases with a 24% positive rate of celiac artery bleeding, and in 19 cases with a 65.5% rate of gastroduodenal artery bleeding. There were no angiographic signs of bleeding in three patients who underwent endoscopy prior to ETAE. Twenty-six patients achieved immediate hemostasis and technical success rate reached 90%. No hemostasis was observed in 27 patients within 30 d after ETAE and clinical success rate was 93%. Recurrent hemorrhage occurred in two patients who drank a lot of wine who were treated by a second embolotherapy in the same way. Five patients underwent transient ischem with light abdominal pain under xiphoid, spontaneous restoration without special treatment. No mucous necrosis happened to 29 cases for ischem of gastroduodenal arteries embolized.

CONCLUSION: ETAE is an effective and safe measure to control acute massive bleeding of duodenal ulcer.

Evaluation of a rabbit rectal VX2 carcinoma model using computed tomography and magnetic resonance imaging

AIM: To establish a rabbit rectal VX2 carcinoma model for the study of rectal carcinoma.

METHODS: A suspension of VX2 cells was injected into the rectum wall under the guidance of X-ray fluoroscopy. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to observe tumor growth and metastasis at different phases. Pathological changes and spontaneous survival time of the rabbits were recorded.

RESULTS: Two weeks after VX2 cell implantation, the tumor diameter ranged 4.1-5.8 mm and the success implantation rate was 81.8%. CT scanning showed low-density foci of the tumor in the rectum wall, while enhanced CT scanning demonstrated asymmetrical intensification in tumor foci. MRI scanning showed a low signal of the tumor on T₁-weighted imaging and a high signal of the tumor on T₂-weighted imaging. Both types of signals were intensified with enhanced MRI. Metastases to the liver and lung could be observed 6 wk after VX2 cell implantation, and a large area of necrosis appeared in the primary tumor. The spontaneous survival time of rabbits with cachexia and multiple organ failure was about 7 wk after VX2 cell implantation.

CONCLUSION: The rabbit rectal VX2 carcinoma model we established has a high stability, and can be used in the study of rectal carcinoma.