Yong-Kwan Cho

Methylation of O6-methylguanine-DNA methyltransferase gene is associated significantly with K-ras mutation, lymph node invasion, tumor staging, and disease free survival in patients with gastric carcinoma

O6‐methylguanine‐DNA methyltransferase (MGMT) can remove O6alkylG DNA adducts. If they are not removed, then the adducts mispair with T during DNA replication, resulting in G‐to‐A mutation. Interrelations between MGMT gene inactivation by promoter methylation, K‐ras mutation, and clinicopathologic features in patients with gastric carcinoma were studied.

Significant Correlation between Serum Level of Hepatocyte Growth Factor and Progression of Gastric Carcinoma

Abstract. Hepatocyte growth factor (HGF) can promote proliferation of many types of tumor cells including gastric cancer cells. To study the role of HGF in the progression of gastric carcinoma, HGF levels were measured by an enzyme immunoassay (EIA) system in sera of gastric cancer patients and followed up the levels after the operation. The mean serum HGF level in 212 healthy control subjects, 140 patients with primary gastric cancer, and 13 patients with recurrent gastric cancer were 0.199 ± 0.073, 0.325 ± 0.209, and 0.578 ± 0.258 ng/ml, respectively. The increase of the levels was significantly correlated with the progression of tumor stage. The levels decreased to normal levels 1 month after curative resection of the tumors. However, the levels did not decrease significantly in nonresected cases. During the follow-up of the patients for several months, the level was significantly increased in recurrent gastric cancer patients, whereas there was no increase in nonrecurrent patients. In conclusion, the serum HGF levels significantly correlated with the aggressiveness of the tumors, suggesting an important role of HGF in the progression of gastric carcinoma.

Helicobacter pylori infection promotes gastric carcinogenesis in a mice model

Debate that Helicobacter pylori might play a causative role in gastric carcinogenesis still exists in spite of the World Health Organization’s definition of H. pylori as a class I carcinogen. In order to define the exact role of H. pylori infection in gastric carcinogenesis, we established a mice model of H. pylori infection.

Long-term evaluation of mice model infected with Helicobacter pylori: focus on gastric pathology including gastric cancer.

Background : Long‐term evaluation of gastric pathology after H. pylori infection is very important in order to reveal its clinical implications, since debate still exists on the gastric carcinogenesis provoked by H. pylori infection in animal models.

Effect of long-term administration of rebamipide on Helicobacter pylori infection in mice.

Background : It has been suggested that chronic, persistent, uncontrolled inflammations in the stomach could provide the basic step for the beginning of carcinogenesis. One of the potential clinical applications of rebamipide is the inhibition of the immunoinflammatory response in gastric mucosa imposed by Helicobacter pylori.

Outcomes after Combined Laparoscopic Gastrectomy and Laparoscopic Cholecystectomy in Gastric Cancer Patients

Background/Aims: The purpose of this study was to determine the effect of performing laparoscopic cholecystectomy on patients undergoing laparoscopic-assisted gastrectomy for gastric cancer. Methods: This single center study involved a retrospective review of a database of 400 patients who underwent consecutive laparoscopic-assisted gastrectomy for early gastric cancer from June 2003 to July 2007. Outcomes in 26 patients who underwent both laparoscopic-assisted gastrectomy and laparoscopic cholecystectomy were compared with outcomes from 364 patients who underwent laparoscopic-assisted gastrectomy without laparoscopic cholecystectomy. Results: There were no postoperative 30-day mortalities in the combined cholecystectomy group. The mean surgery duration, time to first flatus and postoperative hospital stay for the laparoscopic gastric resection without combined operation were 181.7 min, 2.7 days and 9.7 days, respectively, and 196.7 min, 2.6 days and 8.8 days, respectively, for the combined cholecystectomy group. None of the postoperative complications was related to combined cholecystectomy. Conclusion: Performing a combined cholecystectomy prolonged the mean surgery duration by approximately 15 min, but had no effect on surgical outcomes. It appears that performing a cholecystectomy at the same time as laparoscopic gastric resection is safe and feasible in patients with both early gastric cancer and gallbladder disease.

5-Fluorouracil, Mitomycin-C, and Polysaccharide-K versus Uracil-Ftorafur and Polysaccharide-K as Adjuvant Chemoimmunotherapy for Patients with Locally Advanced Gastric Cancer with Curative Resection

Background: Despite the small but significant survival benefit of adjuvant chemotherapy in locally advanced gastric cancer (LAGC), the optimal regimen remains to be determined. We conducted a randomized trial comparing oral (PO) chemoimmunotherapy (CITX) with intravenous (IV) CITX in LAGC patients (stages IB-IIIB) with curative resection (≥ D2 dissection). Methods: The patients were randomized to the IV (5-fluorouracil 500 mg/m2 weekly for 24 weeks, mitomycin-C 8 mg/m2 every 6 weeks × 4) or the PO (uracil-ftorafur (UFT) 400-600 mg/day for 12 months) group. Patients in both groups received PO polysaccharide-K (3 g/day for 4 months). The planned number of patients was 368 for proving the non-inferiority of PO CITX compared to IV CITX for overall survival. Results: The trial was closed prematurely after enrolling 82 patients (44 in the IV group, 38 in the PO group). With a median follow-up of 82 months, there were no significant differences in the 5-year disease-free survival (73% vs. 55%, p = 0.358) and overall survival (77% vs. 66%, p = 0.159) between the 2 groups. The IV group demonstrated a higher incidence of grade 2 or 3 neutropenia, thrombocytopenia, and vomiting. Conclusions: PO CITX with UFT appeared to be at least non-inferior to 5-fluorouracil and mitomycin-C CITX, with lower toxicity in the adjuvant treatment for LAGC.