Eiichiro Toyama

MicroRNA-21 Regulates the Proliferation and Invasion in Esophageal Squamous Cell Carcinoma

Purpose: MicroRNAs are ∼22 nucleotide noncoding RNA molecules that posttranscriptionally regulate gene expression. The aim of this study was (a) to determine a role of microRNA-21 in esophageal squamous cell carcinoma and (b) to elucidate the regulation of the programmed cell death 4 (PDCD4) gene by microRNA-21. Experimental Design: MicroRNA-21 expression was investigated in 20 matched normal esophageal epitheliums and esophageal squamous cell carcinomas and seven esophageal squamous cell carcinoma cell lines (TE6, TE8, TE10, TE11, TE12, TE14, KYSE30) by TaqMan quantitative real-time PCR and in situ hybridization. To evaluate the role of microRNA-21, cell proliferation and invasion were analyzed with anti–microRNA-21–transfected cells. In addition, the regulation of PDCD4 by microRNA-21 was elucidated to identify the mechanisms of this regulation. Results: Of 20 paired samples, 18 cancer tissues overexpressed microRNA-21 in comparison with matched normal epitheliums. Specifically, patients with lymph node metastasis or venous invasion showed significantly high expression of microRNA-21. In situ hybridization for microRNA-21 showed strong positive staining in paraffin-embedded esophageal squamous cell carcinoma tissues. All seven esophageal squamous cell carcinoma cell lines also overexpressed microRNA-21, and anti–microRNA-21–transfected cells showed significant reduction in cellular proliferation and invasion. The PDCD4 protein levels in esophageal squamous cell carcinoma cells have an inverse correlation with microRNA-21 expression. Anti–microRNA-21–transfected cells increased PDCD4 protein expression without changing the PDCD4 mRNA level and increased a luciferase-reporter activity containing the PDCD4-3′ untranslated region construct. Conclusions: MicroRNA-21 targets PDCD4 at the posttranscriptional level and regulates cell proliferation and invasion in esophageal squamous cell carcinoma. It may serve as a novel therapeutic target in esophageal squamous cell carcinoma.

The Relationship between the Glucose Transporter Type 1 Expression and 18F-Fluorodeoxyglucose Uptake in Esophageal Squamous Cell Carcinoma

Objective: Glucose transporter type 1 (Glut1) has been reported to be present in several types of carcinomas. The aims of this study are to evaluate Glut1 expression in both primary tumors and metastatic lymph nodes (LNs) of esophageal squamous cell carcinoma (ESCC) and to assess the relationship between Glut1 expression and 18F-fluorodeoxyglucose (FDG) accumulation. Methods: We immunohistochemically examined the expression of Glut1 in 60 surgically resected primary lesions and 95 metastatic LNs of ESCC and classified them into 3 groups. The FDG accumulation was assessed with a positron emission tomography (PET). Results: In the primary tumors, a high Glut1 expression was found to be significantly associated with advanced lesions: depth of tumor (p < 0.01), LN metastasis (p < 0.05) and advanced pathological stage (p < 0.01). The Glut1 expression of the metastatic LNs significantly correlated with that of each primary tumor (p < 0.001). The PET-positive lesions had a larger size and higher Glut1 expression than the PET-negative lesions in both the primary tumors and metastatic LNs. Conclusions: In both the primary tumors and metastatic LNs of ESCC, the Glut1 expression and tumor size correlated with the FDG accumulation and influence the sensitivity of the PET scan.

A case of thoracoscopically resected benign esophageal schwannoma with high uptake on FDG-PET

We report a rare case of esophageal schwannoma with high uptake of radiotracer on [18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET). A 37-year-old woman underwent surgery for sarcoma of the uterus and received general PET examination for postoperative follow-up, which revealed high uptake at the thoracic esophagus. Esophagography, esophageal endoscopy, endoscopic ultrasonography, and computed tomography (CT) scan confirmed a submucosal tumor, about 20 mm in diameter, in the right wall of the upper thoracic esophagus. We performed thoracoscopic enucleation with the preoperative diagnosis of esophageal leiomyoma or gastrointestinal stromal tumor (GIST). Histopathological examination showed a trabecular arrangement of spindle cells and no evidence of mitosis. Immunohistochemical studies were positive for S-100 protein and negative for c-kit, whereby we diagnosed a benign esophageal schwannoma. Even if benign, schwannomas often show high uptake of FDG, so that the evaluation of whether the tumor is malignant should be made by histological diagnosis. Thoracoscopic resection is less invasive and a clinically useful approach to treat such submucosal tumors of the esophagus.

Tornado Roux-en-Y anastomosis in laparoscopy-assisted distal gastrectomy

The use of laparoscopy-assisted distal gastrectomy has been gradually spreading and it has become one of the standard treatment options for early gastric cancer in Japan. But anastomotic problems are still frequent with this procedure, because of its technical difficulty. We have developed a simple, safe, and speedy Roux-en-Y anastomosis for use in laparoscopy-assisted distal gastrectomy. Here, we describe our technique and the short-term results.

Neuroendocrine tumor of the rectum.

The authors report a case of a neuroendocrine tumor of the rectum. A 57-year-old man was revealed to have a large tumor of the rectum with invasion to the urinary bladder and seminal capsule. After resection, the tumor was revealed to be composed of neuroendocrine cells. Adjuvant chemotherapy using cisplatin and camptothecin-11 was completed, and the patient was without recurrence 6 months after surgery.

Case of cecal volvulus successfully treated with endoscopic colopexy: Cecal volvulus treated endoscopically

We herein report a case of cecal volvulus successfully treated with endoscopic colopexy. A 73‐year‐old man with a high fever and abdominal fullness was diagnosed with ileus caused by cecal volvulus. CT showed a dilated cecum and small intestine without bowel strangulation as well as acute pneumonia. Because the pneumonia increased the risk associated with general anesthesia, we attempted decompression of the bowel using endoscopy to avoid surgery. On day 1, a transanal ileus tube was inserted to the terminal ileum through the dilated cecum. On day 7, the bowel torsion spontaneously released. On day 8, we performed percutaneous endoscopic colopexy to fix the cecum on the abdominal wall and prevent re‐twisting. The patient was discharged on day 15 without postoperative complications. Percutaneous endoscopic colopexy for cecal volvulus may be a treatment option when the risk associated with general anesthesia or surgery is high because of a comorbidity.