Expression of Cellular Oncogenes in Colorectal Cancer : c-myc, c-Ha-ras and c-erbB-2

Although causative factors are not completely defined, carcinogenesis of colorectal cancer is attributed to multiple genetic alterations. The abnormal expressions of oncogenes are regarded to be responsible for the production of malignant phenotype, subsequent invasion and metastasis. From 63 surgically resectable colorectal adenocarcinoma patients, expression of oncogenes in colorectal cancer tissue was evaluated with immunohistochemical staining methods using monoclonal antibodies to products of the oncogenes. To evaluate the possibility of oncogenes as a prognostic factor, we studied the relationship between the expression of oncogenes and the clinicopathologic findings which are well known prognostic factors. Rates of expression in colorectal cancer tissue were 27% for c-myc, 74.6% for c-Ha-ras and 77.8% for c-erbB-2 oncogenes. The positive rate of c-erbB-2 oncogene was higher in the well differentiated group than in the poorly differentiated group. The rates of expression of c-myc and c-Ha-ras oncogenes were significantly correlated each other. Expression of these oncogenes in colorectal cancer were not correlated with the pathologic stage, location of cancer, DNA ploidy pattern and histologic differentiation except between c-erbB-2 and histologic differentiation. In conclusion, there seems to be a possibility that c-erbB-2 could be used as a prognostic factor of colorectal cancer. However, further and more intensive study seems to be required.

Surgical Treatment of Esophageal Perforation Caused by Balloon Catheter and Expandible Metal Stent in a Benign Distal Esophageal Stricture

An esophageal perforation is a condition requiring emergency treatment. Although previously spontaneous ruptures were the most common etiology, as endoscopic and radiologic diagnosis and treatment have developed recently, iatrogenic ruptures due to instrumentation have increased to become the most common cause of esophageal perforations. Generally, the treatment of esophageal stenosis is composed of esophageal dilatation using a Maloney or a Mercury dilator and medical treatment for reflux esophagitis. Recently, balloon-catheter dilatation of the esophagus has produced safe and excellent results, and self-expansible metallic stents has been very useful in controlling malignant strictures of the esophagus with low mortality and morbidity. We experienced an esophageal perforation after balloon dilatation and the insertion of a self-expanding silicone-covered Gianturco stent to the site of the esophageal stenosis which was due to reflux esophagitis. The abdomen was opened through an upper midline incision. There was a 3-cm-long longitudinal laceration on the distal esophagus which was closed transversely as with a Heinecke-Mikulicz pyloroplasty after a debridement. To reinforce the site of esophageal laceration and to prevent esophageal reflux, the gastric fundus was pulled and sutured over the esophageal sutures, and the second-layer mattress suture was made 1 cm proximal to the first sutures, including central ligaments of the diaphragm. To prevent bile reflux, we converted from a Billroth-II to a Roux- en-Y gastrojejunostomy. We followed up for 30 months and found no signs of any esophageal stenosis or gastroesophageal reflux.

Mesenchymal Cell Tumors of the Gastrointestinal Tract

Mesenchymal cell tumors of the intestinal tract originate from connective tissues, muscles, fat, lymphatic tissues, blood vessels, and nerves in and beneath the submucosa. The most common site is the stomach, followed by the small bowel. Among the benign gastric neoplasms of mesodermal origin, those derived from smooth muscles constitute over 90%. Leiomyosarcomas of the stomach represent about 1% to 3% of primary malignant tumors and approximately 20% of submucosal tumors of the stomach. In the small bowel, leiomyoma is the most common benign tumor, and leiomyosarcoma represents about 19% of malignant tumors. The principle of surgical treatment of gastric mesenchymal tumors is local excision with a 2 to 3 cm margin in the surrounding gastric wall. We reviewed 48 cases of mesenchymal cell tumors of the gastrointestinal tract from January 1988 to March 1997 at the Department of Surgery, Namkwang General Hospital and Chonnam University Hospital School. The results are as follows : 1) There were 23 benign and 25 malignant tumors. 2) The most common benign tumor was leiomyoma (41.7%) and the most common malignant tumor was a leiomyosarcoma (47.9%). 3) The most common site was the stomach (52.1%), followed by the small bowel (25%); in the gastric tumor cases, the most common site was the body (60%). 4) The most common clinical manifestation was abdominal pain (37.5%), followed by bleeding (27.1%), a palpable mass, dyspepsia, and weight loss. 5) A wedge resection, a subtotal gastrectomy, or an enucleation of the mass was mainly performed on the stomach. Segmental resection and anastomosis was primarily performed in the small bowel. 6) Among the malignant tumors, a recurrence was noted in 8 patients(32%) : 7 leiomyosarcomas and 1 malignant histiocytoma. 7) The prognosis for a malignant leiomyosarcoma was better than that for an adenocarcinoma and was associated with tumor size and histologic grade (mitosis/10 HFP). However, we could not find any correlation between the prognosis and lymph node metastasis.