Evidence for interspecific hybridization between native white-spotted charr Salvelinus leucomaenis and non-native brown trout Salmo trutta on Hokkaido Island, Japan

Hybrids between native white-spotted charr Salvelinus leucomaenis and non-native brown trout Salmo trutta were identified in streams of Hokkaido, Japan, using both appearance and genetic characters. The DNA analyses indicated that the specimens were hybrids between female S. leucomaenis and male S. trutta. Occurrence of such hybrids implies increased mating opportunities between these species in wild streams.

Cerebral diagnostic and therapeutic angiography for neonatal arteriovenous fistulas

SUMMARY

Cerebral diagnostic and therapeutic angiography for neonatal arteriovenous fistulas is reported. Three neonatal boys with vein of Galen aneurysmal malformation (1 patient) and dural arteriovenous fistulas (2 patients) presented severe congestive heart failure soon after birth, and were treated by transarterial and/or transvenous embolization using various access routes. In the neonatal period, umbilical approach and direct cervical approach provide unique access routes in addition to the usual transfemoral route. Characteristics of neonatal angiography are discussed.

Prognosis of patients with intrahepatic recurrence after hepatic resection for hepatocellular carcinoma: a retrospective study

AIMS

Hepatic resection is the most effective therapy for hepatocellular carcinoma (HCC); however, intrahepatic recurrence is common. Predictors of survival after intrahepatic recurrence have not been fully investigated. To clarify the prognosis and choice of treatment of intrahepatic recurrence after hepatic resection, we conducted a comparative retrospective analysis of 147 patients with HCC who underwent hepatic resection.

METHODS

We retrospectively examined the relations between clinicopathologic factors, including the number of recurrent intrahepatic tumors and long-term prognosis after recurrence in 147 HCC patients who underwent resection. We also examined long-term survival after recurrence based on treatment types and recurrence pattern.

RESULTS

Patients with multiple tumors (n=83) showed less tumor differentiation, more frequent portal invasion, a higher alpha-fetoprotein level, and larger tumors than did patients with solitary tumor (n=64). In the solitary tumor group, local ablation therapy and repeat hepatic resection were performed in 25 and 10, respectively. In the multiple tumor group, 59 were treated by transarterial chemoembolization. Multivariate analysis showed intraoperative blood transfusion and multiple tumors to be independent risk factors for poor cancer-related survival after recurrence. By subset analysis based on treatment types and recurrence pattern, survival after recurrence was significantly better in patients treated by local ablation therapy than those treated by other therapies in both solitary and multiple tumor groups.

CONCLUSIONS

For patients with solitary recurrence, a good prognosis is predicted. Local ablation therapy is a best candidate for treatment of solitary and multiple intrahepatic recurrences after hepatic resection.

Long-term phenotypic, functional and genetic stability of cancer-specific T-cell receptor (TCR) alphabeta genes transduced to CD8+ T cells

In adoptive T-cell transfer as an intervention for malignant diseases, retroviral transfer of T-cell receptor (TCR) genes derived from CD8(+) cytotoxic T-lymphocyte (CTL) clones provides an opportunity to generate a large number of T cells with the same antigen specificity. We cloned the TCR-alphabeta genes from a human leukocyte antigen (HLA)-A(*)2402-restricted CTL clone specific for MAGE-A4(143-151). The TCR-alphabeta genes were transduced to 99.2% of non-TCR expressing SupT1, a human T-cell line, and to 12.7-32.6% of polyclonally activated CD8(+) T cells by retroviral transduction. As expected, TCR-alphabeta gene-modified CD8(+) T cells showed cytotoxic activity and interferon-gamma production in response to peptide-loaded T2-A(*)2402 and tumor cell lines expressing both MAGE-A4 and HLA-A(*)2402. A total of 24 clones were established from TCR-alphabeta gene-transduced peripheral blood mononuclear cells and all clones were functional on a transduced TCR-dependent manner. Four clones were kept in culture over 6 months for analyses in detail. The transduced TCR-alphabeta genes were stably maintained phenotypically, functionally and genetically. Our results indicate that TCR-transduced alphabeta T cells by retroviral transduction represent an efficient and promising strategy for adoptive T-cell transfer for long term.

Antitumor effects of the MIG and IP-10 genes transferred with poly [D,L-2,4-diaminobutyric acid] on murine neuroblastoma

The number of tumor-infiltrating lymphocytes is known to be related to outcomes in patients with a variety of malignancies. Interferon (IFN) gamma-inducible protein-10 (IP-10) and monokine induced by IFNgamma (MIG) have chemotactic effects on activated T lymphocytes and natural killer (NK) cells. The aim of this study was to evaluate the antitumor effects of exogenous expression of the MIG and IP-10 genes delivered to solid tumors by poly [D,L-2,4-diaminobutyric acid] (PDBA). The murine MIG and IP-10 genes were transfected into mouse neuroblastoma cells with PDBA. MIG and IP-10 levels in supernatants of transfected cells were measured by enzyme-linked immunosorbent assay. The chemotactic activities of MIG and IP-10 in the supernatants of cell cultures were measured by chemotaxis assay. Tumors were injected in vivo with PDBA/pmMIGColon, two colonsIP-10 complexes to evaluate the effects of these genes on tumor volume and survival time of mice. Transfected PDBA/pmMIGColon, two colonsIP-10 complexes produced MIG and IP-10 protein in vitro. MIG and IP-10 proteins secreted into the culture medium showed chemotactic activity. MIG and IP-10 gene therapy with the PDBA system in vivo significantly inhibited tumor growth and prolonged survival time of mice. In conclusion, PDBA-mediated MIG and IP-10 gene therapy may be useful for treatment of solid tumors.

Long-term quality of life after laparoscopy-assisted distal gastrectomy for gastric cancer

BACKGROUND

Laparoscopy-assisted distal gastrectomy (LAG) is gaining acceptance for treating early gastric cancer. However, the long-term quality of life after LAG for gastric cancer is unknown. This study compared the long-term quality of life after LAG versus open distal gastrectomy (ODG) for early gastric cancer.

METHOD

This study included 53 patients who underwent LAG and 37 patients who underwent ODG for treatment of early gastric cancer. Quality of life was evaluated on the basis of a 22-item questionnaire that addressed food tolerance and mental and physical conditions, scored on a scale of 1-3.

RESULTS

The mean follow-up periods after LAG and ODG were 99.3 and 97.0 months, respectively. Although the majority of patients who had undergone LAG were consuming a normal diet and had weight loss of less than 5 kg, all 22 items and the total score of the LAG group were comparable to those of the ODG group. However, the incidence of postoperative intestinal obstruction was significantly lower in the LAG group than in the ODG group (1% vs. 13%, p < 0.05).

CONCLUSIONS

LAG is equivalent to ODG with respect to long-term quality of life and is associated with a reduced incidence of postoperative intestinal obstruction.

Prognosis and postoperative lymphocyte count in patients with hepatocellular carcinoma who received intraoperative allogenic blood transfusion: a retrospective study

AIMS

The effect of perioperative blood transfusion on the survival of hepatocellular carcinoma (HCC) has not been fully investigated. To clarify the prognostic value of intraoperative allogenic blood transfusion, we conducted a comparative retrospective analysis of 224 patients with HCC who underwent hepatic resection.

METHODS

We compared clinicopathologic background and survival after hepatic resection between patients who received intraoperative blood transfusion (n=101) and those who did not (n=123).

RESULTS

Patients with blood transfusion had a larger tumor and more frequent vascular invasion than those without blood transfusion. The 5-year cancer-related survival rate after hepatic resection, but not the disease-free survival rate, was significantly lower in patients who underwent blood transfusion than in those who did not (38.3% vs. 66.7%, P<0.01). Multivariate analysis showed intraoperative blood transfusion (P=0.02), microscopic portal invasion (P<0.01), and preoperative serum alpha-fetoprotein elevation (P=0.03) to be independent risk factors for poor outcome after hepatic resection. The negative effect of blood transfusion on postoperative survival was observed only in patients with a tumor larger than 50mm in diameter. The absolute peripheral blood lymphocyte count on postoperative day 1 was significantly lower in patients who underwent blood transfusion (880/mm(3)) than in those who did not (1081/mm(3)) (P<0.01).

CONCLUSIONS

Our data suggest that intraoperative blood transfusion results in immunosuppression in the early postoperative period, allowing for progression of residual HCC after resection. Therefore, intraoperative allogenic blood transfusion should be avoided in patients with resectable HCC, particularly in those with a large tumor.

Laparoscopic sentinel node navigation achieved by infrared ray electronic endoscopy system in patients with gastric cancer

BACKGROUND

The sentinel node (SN) concept has attracted considerable attention recently for the treatment of patients with early gastric cancer (EGC). This study evaluated the feasibility of laparoscopic SN navigation achieved by means of an infrared ray electronic endoscopy (IREE) system with indocyanine green (ICG) injection in patients with EGC.

METHODS

Laparoscopic SN navigation was performed for 16 patients with preoperatively diagnosed EGC. After identification of SNs, routine laparoscopically assisted distal gastrectomy with lymphadenectomy was performed. Lymph nodes were examined histologically for metastasis by hematoxylin and eosin staining on one section of each node.

RESULTS

One or more SNs and lymphatic basins were detected in all 16 patients. The average number of SNs detected was 2.9. Lymph node metastasis was found in 2 of the 16 patients (13%). In one of these two patients, lymph node metastasis was found in SNs. In the other patient, metastasis was found in a non-SN rather than a SN, but in the same lymphatic basin. The accuracy of this detection method was 94%, and there was one false-negative case. No adverse events occurred after injection of ICG.

CONCLUSION

Laparoscopic SN navigation by means of IREE combined with ICG injection is feasible for patients undergoing laparoscopic surgery for EGC.

A multicenter study on laparoscopic surgery for colorectal cancer in Japan

BACKGROUND

Laparoscopic colectomy for malignant disease technically is feasible but not widely accepted because there are no large-series studies or data on long-term outcomes. A retrospective, multicenter study investigating a large series of patients was conducted in Japan to evaluate preliminary long-term results of laparoscopic surgery for colorectal cancer.

METHODS

The study group comprised 2,036 patients who underwent laparoscopic colorectal resection April 1993 to August 2002 in 12 participating surgical units (Japanese Laparoscopic Surgery Study Group).

RESULTS

Of the 1,495 patients with colon cancer, 781 (59%) had International Union Against Cancer (UICC) stage I, 248 (19%) had stage II, and 284 (22%) had stage III disease. Cancer recurred for 61 (4.1%) of 1,367 curatively treated patients (median follow-up period, 32 months; range, 6-125 months). The 5-year survival rate was 96.7% for stage I, 94.8% for stage II, and 79.6% for stage III disease. Of the 541 patients with rectal cancer, 220 (56%) had stage I, 62 had (16%) stage II, and 108 (28%) had stage III disease. Cancer recurred for 30 (5.6%) of 476 curatively treated patients (median follow-up period, 25 months; range 6-102 months). The 5-year survival rate was 95.2% for stage I, 85.2% for stage II, and 80.8% for stage III disease.

CONCLUSIONS

The findings indicate that laparoscopic surgery for colorectal cancer yields an oncological outcome as good as that reported for conventional open surgery in the Japanese Registry for all disease stages.

Preoperative transcatheter arterial chemoembolization reduces long-term survival rate after hepatic resection for resectable hepatocellular carcinoma

AIMS

To study the effect of preoperative transcatheter arterial chemoembolization (TACE) on long-term survival after hepatic resection for hepatocellular carcinoma (HCC), we conducted a comparative analysis in 235 HCC patients who underwent hepatic resection with a curative intent.

METHODS

We compared clinicopathologic background, mortality, and survival rates after hepatic resection between those who underwent preoperative TACE (n=109) and those who did not (n=126).

RESULTS

One hundred and two patients in the TACE group (93.6%) received TACE only once. The mean interval between TACE and hepatic resection was 33.1days. Patients in the TACE group were younger than those in the non-TACE group, and liver cirrhosis and non-anatomical hepatic resection were more prevalent in this group. The 5-year overall survival rate after hepatic resection was significantly lower in the TACE group (28.6%) than in the non-TACE group (50.6%), especially in patients without cirrhosis or with stage I or II tumor. There was no difference between the two groups in mortality or disease-free survival after hepatic resection. Multivariate analysis showed preoperative TACE, preoperative aspartate aminotransferase elevation, and microscopic portal invasion to be independent risk factors for a poor outcome after hepatic resection.

CONCLUSIONS

Preoperative TACE should be avoided for patients with resectable HCC, especially for those without cirrhosis or with an early stage tumor.

Usefulness of transanal endoscopic surgery for carcinoid tumor in the upper and middle rectum

BACKGROUND

This study evaluated the indications and outcome for transanal endoscopic surgery (TES) used to manage rectal carcinoid tumor as compared with those of conventional transanal local resection (TAR).

METHODS

The retrospective study subjects were 28 patients with rectal carcinoid tumor treated by TES (n = 17) or TAR (n = 11) between January 1995 and December 2001. Patient and tumor characteristics, operative results, and postoperative outcomes were compared between the two groups.

RESULTS

The distance from the anal verge to the distal tumor margin in the TES group (range, 4-12 cm; median, 6.8 cm) was significantly greater than in the TAR group (range, 3-6 cm; median, 4.5 cm) (p = 0.001). The median tumor diameter was 5.5 mm (range, 3-11 mm) in the TES group and 5.0 mm (range, 3-8 mm) in the TAR group, showing no statistical difference. Microscopically, resected specimens in both groups were typical carcinoid tumors restricted to the submucosal layer. No recurrence was noted in either group.

CONCLUSION

Whereas TES is useful for patients with small rectal carcinoid tumor of typical histology within the submucosal layer in the upper and middle rectum, TAR is effective for accessing the lower rectum.

Liver metastasis and ICAM-1 mRNA expression in the liver after carbon dioxide pneumoperitoneum in a murine model

BACKGROUND

Liver metastasis of colorectal malignancies is an important prognostic factor. Several studies have demonstrated that carbon dioxide (CO2) pneumoperitoneum enhances liver metastasis in animal models. Little is known about intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-(alpha) mRNA expression in the liver after CO2 pneumoperitoneum.

METHODS

Forty-five male BALB/c mice were randomly divided into three groups after intra-splenic tumor cell (colon 26) inoculation and the following procedures were performed: CO2 pneumoperitoneum (n = 15), open laparotomy (n = 15), and anesthesia alone (n = 15). On day 7 after each procedure, the livers were excised and the number and diameter of the tumor nodules and the cancer index score were determined. Another 90 male BALB/c mice were randomly divided into three groups as described above, and they underwent each procedure (n = 30 each). After each procedure, the livers were excised on days 0, 1, 3, and ICAM-1 and TNF-alpha mRNA expression were examined by real-time RT-PCR using SYBR Green I.

RESULTS

The number of tumor nodules and the cancer index score were larger in the CO2 pneumoperitoneum group than in the control group (p < 0.05). The mean diameter of the tumor nodules was not different among the three groups. The expression of ICAM-1 in the CO2 pneumoperitoneum group was higher than that in the other groups on day 1 (p < 0.05), and the TNF-alpha mRNA was higher than that in the control group on day 1 (p < 0.05).

CONCLUSIONS

CO2 pneumoperitoneum enhances liver metastasis compared with anesthesia alone, and ICAM-1 expression in the liver after the pneumoperitoneum plays an important role in establishing liver metastasis in a murine model.

Morphological changes in hepatic vascular endothelium after carbon dioxide pneumoperitoneum in a murine model

BACKGROUND

Liver metastasis is an important prognostic factor in advanced colorectal cancer. Several studies have demonstrated that carbon dioxide (CO2) pneumoperitonem enhances liver metastasis in an animal model. In the present study, we used scanning electron microscopy (SEM) to investigate morphological changes in hepatic vascular endothelium after CO2 pneumoperitoneum in a murine model.

METHODS

Thirty-three male BALB/c mice were randomized to undergo pneumoperitoneum (CO2, air, or helium), open laparotomy, and anesthesia alone. After each procedure, the animals' livers were excised at days 0, 1, and 3 and examined by SEM.

RESULTS

In the CO2 pneumoperitoneum group, we observed rough surface and derangement of the hepatic vascular endothelial cells and intercellular clefts on day 1. In the other groups, no major morphologic changes were observed at any time.

CONCLUSIONS

Hepatic vascular endothelium changes after CO2 pneumoperitoneum. Such characteristic changes may play an important role in establishing liver metastasis after CO2 pneumoperitoneum.

Increased peritoneal dissemination after laparotomy versus pneumoperitoneum in a mouse cecal cancer model

BACKGROUND

The effect of carbon dioxide (CO(2)) pneumoperitoneum on the liberation of cancer cells from the primary tumor is not clear. This study investigated the influence of laparotomy versus CO(2) pneumoperitoneum on the progression of colon cancer with serosal invasion in a mouse model.

METHODS

Pieces of human colon adenocarcinoma (HT29) tumor were implanted in the cecal wall of 45 BALB/c nude mice. Each mouse underwent one of three procedures: laparotomy, CO(2) pneumoperitoneum, or anesthesia (control). Three weeks later, the size and weight of cecal tumors, the number of nodules, and the tumor volume score of peritoneal dissemination were examined. Another 45 mice were treated in the same way. The cecal tumor was resected on days 1, 3, or 5 after treatment. Total RNA was isolated from the resected tumors. The expression of E-cadherin and beta-1 integrin messenger RNA (mRNA) was examined by semiquantitative real-time reverse transcriptase-polymerase chain reaction assay.

RESULTS

Significantly more nodules of peritoneal dissemination were found in the laparotomy group than in the control group (p < 0.05). The tumor volume score of peritoneal dissemination in the laparotomy group was significantly higher than in the other two groups (p < 0.05). The expression of E-cadherin mRNA at day 5 in the laparotomy group was significantly less than in the other two groups (p < 0.05). There were no differences in beta-1 integrin among three groups.

CONCLUSIONS

Peritoneal dissemination was more extensive after laparotomy than after CO(2) pneumoperitoneum in a mouse model of cecal cancer with serosal invasion. Decreased expression of E-cadherin mRNA in tumors after laparotomy, but not after CO(2) pneumoperitoneum, may be associated with the increase in peritoneal dissemination.

Port-site metastasis after CO2 pneumoperitoneum

BACKGROUND

Port-site metastasis is a continuing problem in laparoscopic cancer surgery. To clarify the role of adhesion molecules in the development of port-site metastasis, particularly with regard to prevention, we performed experiments in which port-site metastasis was inhibited using antibodies against extracellular matrix proteins or the active Arg-Gly-Asp (RGD) peptide after CO2 pneumoperitoneum in a murine model.

METHODS

We examined the development of port-site metastasis under the following conditions: (1) CO2 pneumoperitoneum with or without hyaluronic acid and anti-integrin or anti-CD44 antibody and (2) CO2 pneumoperitoneum and a RGD peptide or pseudo-RGD sequence peptide (FC-336). BALB/c mice ( n = 130) were injected with 5 x 10(5) human gastric cancer cells (MKN45) and either antibody or peptide, treated with CO2 pneumoperitoneum, and injected intraperitoneally with antibody or peptide for 5 days. Three weeks after CO2 pneumoperitoneum, the frequency and weight of port-site metastatic tumors were determined.

RESULTS

Anti-integrin antibody significantly decreased the weight of port-site metastatic tumors without hyaluronic acid (control vs anti-integrin: 8.2 +/- 7.1 vs 3.6 +/- 4.5 mg; p < 0.05) but not the frequency of port-site metastases. With hyaluronic acid, the frequency of port-site metastasis and the weight of port-site metastatic tumors were significantly decreased both by anti-integrin and by anti-CD44 antibody (control vs anti-integrin and anti-CD44; 95% and 8.5 +/- 7.2 mg vs 50% and 3.1 +/- 4.3 mg and 55% and 3.3 +/- 5.1 mg, respectively; p < 0.05). RGD peptide and FC-336 also inhibited port-site metastasis in a dose-dependent manner.

CONCLUSION

Cell adhesion molecules integrin and CD44 play an important role in the development of port-site metastasis after laparoscopic cancer surgery. Intraperitoneal injection of RGD peptide or pseudo-RGD sequence peptide (FC-336) can prevent port-site metastasis.

Laparoscopy-assisted distal gastrectomy for early gastric cancer in obese and nonobese patients

BACKGROUND

Conventional open gastrectomy has been reported to result in increased morbidity in obese patients. To date, there has been no study evaluating laparoscopic gastrectomy in such patients; therefore, we assessed the short-term results of this procedure in a group of obese patients.

METHODS

The study included 99 consecutive patients who underwent laparoscopy-assisted distal gastrectomy (LDG) for the cure of early gastric cancer. The patients were divided into two groups: obese (body mass index [BMI] > or =25.0, n = 16) and nonobese (BMI <25.0, n = 83). Patient characteristics, operative details, and postoperative outcomes were compared and analyzed.

RESULTS

Patient characteristics, including age, sex, American Society of Anesthesiologists (ASA) status, and disease stage, were not different between obese and nonobese patients. Operating time was significantly longer in obese patients than in nonobese patients (271 vs 239 min, p < 0.05). However, there was no significant difference between obese and nonobese patients in time to first flatus (3.7 vs 3.3 days), time to solid diet (6.3 vs 5.2 days), length of postoperative hospital stay (18.7 vs 17.9 days), or frequency of major (25% vs 16%) and minor (19% vs 12%) postoperative complications. There were no conversions to conventional open surgery and no perioperative deaths.

CONCLUSION

The only difference between our two study groups was that LDG required a longer operating time in obese patients; morbidity and length of hospital stay were not increased. Thus, we believe that LDG is likely to become the treatment of choice for obese patients with early gastric cancer.

Laparoscopically assisted distal gastrectomy for early gastric cancer in the elderly

Background

Open gastrectomy is associated with increased morbidity and a longer hospital stay than laparoscopically assisted gastrectomy. The aim of this study was to clarify the value of laparoscopically assisted distal gastrectomy (LDG) in the elderly, in whom co-morbid disease is generally more common.

Methods

Forty-five elderly patients (aged 70 years or more) and 57 younger patients who underwent LDG, and 28 elderly patients who underwent open distal gastrectomy (ODG) for early gastric cancer between January 1994 and April 2003 were studied. Demographics and postoperative outcomes were compared.

Results

Co-morbidity was more common in elderly patients than in younger patients who underwent LDG (25 of 45 versus 16 of 57; P = 0·004). The postoperative complication rate, time to solid diet and postoperative hospital stay were similar in these two groups. Elderly patients who underwent LDG had a significantly reduced medical complication rate (two of 45 versus six of 28; P = 0·023), time to first flatus (3·7 versus 4·2 days; P = 0·042), time to solid diet (4·6 versus 5·5 days; P = 0·011) and postoperative hospital stay (16·3 versus 23·9 days; P = 0·011) than elderly patients who had ODG.

Conclusion

LDG offers particular advantages to elderly patients with early gastric cancer, including rapid return of gastrointestinal function, fewer complications and a shorter hospital stay.

Development and progression of diabetic retinopathy in patients with Type 1 diabetes who are positive for GAD autoantibody

AIMS

To investigate the relationship between autoantibodies to glutamic acid decarboxylase (GAD) and proliferative diabetic retinopathy (PDR) to assess the role of autoimmunity in retinopathy.

METHODS

Patients with Type 1 diabetes for more than 10 years who had been diagnosed under age 30 (13-28 years) were studied. They were classified into three groups. The PDR group consisted of 22 patients, the pre-PDR group was 26 patients, while the non-DR group was 32 patients who had Type 1 diabetes without retinopathy. Blood was collected to measure autoantibodies to GAD, and the relationship between PDR and GAD positivity was investigated in a cross-sectional study.

RESULTS

The highest positivity rate of GAD autoantibodies was 50.0% in the non-DR group, followed by the pre-PDR group (30.8%) and the PDR group (18.2%).

CONCLUSIONS

Production or existence of GAD autoantibodies may contribute to the prevention of retinopathy.

Indoleamine 2,3-Dioxygenase is Necessary for Cytolytic Activity of Natural Killer Cells

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan catabolic enzyme that is widely distributed in various tissues. In peripheral blood mononuclear cells (PBMCs), production of IDO by macrophages or dendritic cells has been reported to inhibit T-cell activation and proliferation. In the present study, we have determined that other phenotypes of PBMCs also express IDO. In cultures of PBMCs, IDO was found predominantly in monocyte by immunohistochemistry. Reverse transcriptase polymerase chain reaction analysis showed that IDO mRNA was expressed in T lymphocytes, B lymphocytes and natural killer (NK) cells and that expression was increased upon activation with interferon-gamma. The cytotoxicity of NK cells against K562 and HepG2 cells was reduced by IDO inhibitor. These results suggest that IDO in NK cells is essential for NK cells to generate killing activity against cancer cells.

Current status of laparoscopic gastrectomy for cancer in Japan

Because of the increased incidence of early gastric cancer in Japan, minimally invasive laparoscopic approaches to gastric malignancies have been under development since 1991. Laparoscopic local resection of the stomach, i.e., laparoscopic wedge resection (LWR) and intragastric mucosal resection (IGMR), is used to treat mucosal cancer without lymph node metastasis. Laparoscopy-assisted distal gastrectomy (LADG) is used to treat early gastric cancer with risk factors for regional lymph node metastasis. A survey conducted by the Japan Society for Endoscopic Surgery showed that 1428 LWRs, 260 IGMRs, and 2600 LADGs were performed between 1991 and 2001 in departments of endoscopic surgery in Japan. Laparoscopic gastrectomy for gastric cancer is still under development in Japan. According to short-term results reported by a small group of surgeons, laparoscopic approaches to gastric cancer provide for minimal invasion, early recovery, and decreased morbidity and mortality. If the advantages can be confirmed in one or more multicenter randomized control studies of the long-term outcome of patients undergoing laparoscopic gastrectomy for gastric cancer, the procedure should come into wide acceptance and use.