Development of alveolar and airway cells from human iPS cells: toward SARS-CoV-2 research and drug toxicity testing.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). SARS-CoV-2 enters host cells by binding with the receptor angiotensin-converting enzyme 2 (ACE2). While ACE2 is expressed in multiple cell types, it has been implicated in the clinical progression of COVID-19 as an entry point for SARS-CoV-2 into respiratory cells. Human respiratory cells, such as airway and alveolar epithelial type II (ATII) cells, are considered essential for COVID-19 research; however, primary human respiratory cells are difficult to obtain. In the present study, we generated ATII and club cells from human induced pluripotent stem cells (hiPSCs) for SARS-CoV-2 infection and drug testing. The differentiated cells expressed ATII markers (SFTPB, SFTPC, ABCA3, SLC34A2) or club cell markers (SCGB1A1 and SCGB3A2). Differentiated cells, which express ACE2 and TMPRSS2, were infected with SARS-CoV-2. Remdesivir treatment decreased intracellular SARS-CoV-2 viral replication and, furthermore, treatment with bleomycin showed cytotoxicity in a concentration-dependent manner. These data suggest that hiPSC-derived AT2 and club cells provide a useful in vitro model for drug development.

Phase II study of cisplatin/pemetrexed combined with bevacizumab followed by pemetrexed/bevacizumab maintenance therapy in patients with EGFR-wild advanced non-squamous non-small cell lung cancer.

PURPOSE: This phase II study was performed to evaluate the efficacy and safety of cisplatin/pemetrexed combined with 15 mg/kg of bevacizumab followed by pemetrexed/bevacizumab maintenance therapy as first-line chemotherapy in advanced non-squamous non-small cell lung cancer (NSCLC) limited to epidermal growth factor receptor (EGFR)-wild type. PATIENTS AND METHODS: Fifty patients with advanced or metastatic EGFR-wild type NSCLC aged < 75 years old were enrolled in the study. The patients were treated with four cycles of cisplatin (75 mg/m2, day 1), pemetrexed (500 mg/m2, days 1), and bevacizumab (15 mg/kg, day 1), every 3 weeks, followed by pemetrexed plus bevacizumab maintenance until progression for achieving a response over stable disease after induction chemotherapy. RESULTS: Partial response and stable disease were observed in 35 (objective response rate: 70, 95% CI: 55.4-82.1%) and 9 patients, respectively, and 39 (78%) patients received pemetrexed plus bevacizumab maintenance therapy. Median progression-free survival and overall survival periods were 12.0 months (95% CI: 7.5-16.5 months) and 31.0 months (95% CI: 22.2-39.8 months), respectively. Grade 3 adverse events included neutropenia (14%), nausea (10%), anorexia (18%), and hypertension (8%). Coagulation disorder was observed in one patient, but all of these events were reversible and resulted in no treatment-related deaths. CONCLUSION: The combination of cisplatin/pemetrexed/bevacizumab followed by pemetrexed/bevacizumab maintenance therapy exhibited favorable efficacy and manageable toxicity profiles in patients with EGFR-wild type non-squamous NSCLC (UMIN-CTR number: UMIN000003645).

A Four-Center Retrospective Study of the Efficacy and Toxicity of Low-Dose Trimethoprim-Sulfamethoxazole for the Treatment of Pneumocystis Pneumonia in Patients without HIV Infection.

The dose of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of Pneumocystis pneumonia (PCP) in patients without human immunodeficiency virus (HIV) infection has not been verified. The aim of this study was to investigate the efficacy and toxicity of a low-dose TMP-SMX regimen in such patients. A retrospective study was conducted in four hospitals. We reviewed the medical records of patients with PCP but not HIV (non-HIV-PCP) who were treated with TMP-SMX between 2003 and 2016. The patients were divided into conventional-dose (TMP, 15 to 20 mg/kg/day) and low-dose (TMP, <15 mg/kg/day) groups after patients who received high-dose (TMP, >20 mg/kg/day) treatment were excluded. Grouping was done according to a correction dose, which was based on renal function. Eighty-two patients had non-HIV-PCP. The numbers of patients who received high-, conventional-, and low-dose treatments were 5, 36, and 41, respectively. Kaplan-Meier analysis for death associated with PCP showed no statistically significant difference in survival rates between the conventional- and low-dose groups. Ninety-day cause-specific mortality rates were 25.0% and 19.5% in the conventional-dose and low-dose groups (P = 0.76), respectively. Adverse events that were graded as ≥3 according to the Common Terminology Criteria for Adverse Events (version 4.0) (National Cancer Institute, 2010) were 41.7% and 17.1% in the conventional-dose and low-dose groups (P = 0.02), respectively. Moreover, vomiting (P = 0.03) and a decrease in platelet count (P = 0.03) occurred more frequently in the conventional-dose group. Treatment of non-HIV-PCP with low-dose or conventional-dose TMP-SMX produces comparable survival rates; however, the low-dose regimen is better tolerated and associated with fewer adverse effects.

Two Cases of Proteinase 3-Anti-Neutrophil Cytoplasmic Antibody (PR3-ANCA)-related Nephritis in Infectious Endocarditis.

We herein report two cases of proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA)-related nephritis in infectious endocarditis. In both cases, the patients were middle-aged men with proteinuria and hematuria, hypoalbuminemia, decreased kidney function, anemia, elevated C-reactive protein (CRP) levels, and PR3-ANCA positivity. Each had bacteremia, due to Enterococcus faecium in one and Streptococcus bovis in the other. One patient received aortic valve replacement therapy for aortic regurgitation with vegetation, and the other underwent tricuspid valve replacement therapy and closure of a ventricular septic defect to treat tricuspid regurgitation with vegetation. These patients' urinary abnormalities and PR3-ANCA titers improved at 6 months after surgery following antibiotic treatment without steroid therapy.

Activation of aryl hydrocarbon receptor mediates suppression of hypoxia-inducible factor-dependent erythropoietin expression by indoxyl sulfate.

Indoxyl sulfate (IS) is a representative uremic toxin that accumulates in the blood of patients with chronic kidney disease (CKD). In addition to the involvement in the progression of CKD, a recent report indicates that IS suppresses hypoxia-inducible factor (HIF)-dependent erythropoietin (EPO) production, suggesting that IS may also contribute to the progression of renal anemia. In this report, we provide evidence that aryl hydrocarbon receptor (AhR) mediates IS-induced suppression of HIF activation and subsequent EPO production. In HepG2 cells, IS at concentrations similar to the blood levels in CKD patients suppressed hypoxia- or cobalt chloride-induced EPO mRNA expression and transcriptional activation of HIF. IS also induced AhR activation, and AhR blockade resulted in abolishment of IS-induced suppression of HIF activation. The HIF transcription factor is a heterodimeric complex composed of HIF-α subunits (HIF-1α and HIF-2α) and AhR nuclear translocator (ARNT). IS suppressed nuclear accumulation of the HIF-α-ARNT complex accompanied by an increase of the AhR-ARNT complex in the nucleus, implying the involvement of interactions among AhR, HIF-α, and ARNT in the suppression mechanism. In rats, oral administration of indole, a metabolic precursor of IS, inhibited bleeding-induced elevation of renal EPO mRNA expression and plasma EPO concentration and strongly induced AhR activation in the liver and renal cortex tissues. Collectively, this study is the first to elucidate the detailed mechanism by which AhR plays an indispensable role in the suppression of HIF activation by IS. Hence, IS-induced activation of AhR may be a potential therapeutic target for treating renal anemia.

Indoxyl sulfate exacerbates low bone turnover induced by parathyroidectomy in young adult rats.

Low-turnover bone disease is one of the bone abnormalities observed in patients with chronic kidney disease (CKD) and is recognized to be associated with low serum parathyroid hormone (PTH) level and skeletal resistance to PTH. Indoxyl sulfate (IS) is a representative uremic toxin that accumulates in the blood as renal dysfunction progresses in CKD patients. A recent in vitro study using an osteoblastic cell culture system suggests that IS has an important role in the pathogenesis of low bone turnover through induction of skeletal resistance to PTH. However, the effects of IS on the progression of low bone turnover have not been elucidated. In the present study, we produced rats with low bone turnover by performing parathyroidectomy (PTX) and fed these rats a diet containing indole, a precursor of IS, to elevate blood IS level from indole metabolism. Bone metabolism was evaluated by measuring histomorphometric parameters of secondary spongiosa of the femur. Histomorphometric analyses revealed significant decreases in both bone formation-related parameters and bone resorption-related parameters in PTX rats. In indole-treated PTX rats, further decreases in bone formation-related parameters were observed. In addition, serum alkaline phosphatase activity, a bone formation marker, and bone mineral density of the tibia tended to decrease in indole-treated PTX rats. These findings strongly suggest that IS exacerbates low bone turnover through inhibition of bone formation by mechanisms unrelated to skeletal resistance to PTH.

Clinical outcomes in elderly patients administered gefitinib as first-line treatment in epidermal growth factor receptor-mutated non-small-cell lung cancer: retrospective analysis in a Nagano Lung Cancer Research Group study.

The clinical efficacy and outcomes of gefitinib therapy as a first-line treatment for elderly patients with non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations were analyzed retrospectively. We analyzed chemotherapy-naïve NSCLC patients aged 75 years or older who had EGFR mutations (exon 19 deletion mutation or L858R), who were initially treated with gefitinib (250 mg) once daily in Nagano Prefecture. A total of 55 patients (16 men, 39 women) with a median age of 81.1 years (range; 75-94 years) treated between April 2007 and July 2012 were analyzed. The overall response rate and disease control rate were 72.7 % (95 % confidence interval (CI); 59.5-82.9 %) and 92.7 % (95 % CI; 82.0-97.6 %), respectively. Median progression-free survival and overall survival from the start of gefitinib treatment were 13.8 months (95 % CI; 9.9-18.8 months) and 29.1 months (95 % CI; 22.4 months-not reached), respectively. Two-year survival rate was 59.5 % (95 % CI; 41.0-78.0 %). Major grade 3 toxicities were skin rash (1.8 %) and increased levels of aspartate aminotransferase or alanine aminotransferase (7.3 %). First-line treatment with gefitinib for elderly EGFR-mutated NSCLC patients was effective and well tolerated. The results suggest that first-line gefitinib should be considered as a preferable standard treatment in elderly patients with advanced NSCLC harboring EGFR mutations.

Phase I/II study of S-1 combined with biweekly irinotecan chemotherapy in previously treated advanced non-small cell lung cancer.

PURPOSE: This phase I/II study was designed to evaluate a combination of irinotecan and S-1 a new regimen for salvage chemotherapy in patients with advanced or metastatic non-small cell lung cancer (NSCLC). METHODS: The study group comprised patients with advanced or metastatic NSCLC who had previously received at least one platinum-containing chemotherapy. Patients received irinotecan on days 1, 15 and oral S-1 (40 mg/m(2) twice daily as a fixed dose) on day 1 to 14 of a 28-day cycle. RESULTS: In the phase I part, irinotecan was given in escalating doses of 70 (Level 1), 80 (Level 2), and 90 mg/m(2) (Level 3). Three of the 5 patients given Level 3 had dose-limiting toxicity, and Level 2 (80 mg/m(2) of irinotecan) was designated as the recommended dose. In phase II, 38 patients received a median of 7.4 cycles of irinotecan at the recommended dose. The overall response rate was 15.8 % (90 % confidence interval (CI): 6.1-25.5 %), and the median progression-free and overall survival times were 4.5 months (95 % CI: 3.5-5.0) and 15.0 months (95 % CI: 9.5-20.6) months, respectively. Toxicity was generally mild. Grade 3 or higher toxicity included neutropenia in 17.9 % of the patients, thrombocytopenia in 5.1 % and nausea in 7.7 %. CONCLUSION: Combination chemotherapy with S-1 and irinotecan was considered an effective salvage regimen in patients with advanced or metastatic NSCLC.

Gefitinib as first-line treatment in elderly epidermal growth factor receptor-mutated patients with advanced lung adenocarcinoma: results of a Nagano Lung Cancer Research Group study.

UNLABELLED: Efficacy of first-line gefitinib for elderly epidermal growth factor receptor mutated patients with lung adenocarcinoma is uncertain. This study was aimed to investigate efficacy of gefitinib for such population. The primary endpoint was response rate (RR) and at least 12 cases were needed. Overall RR was 59% (95% confidence interval, 33%-81%) and first-line gefitinib was effective for elderly patients. INTRODUCTION: Feasibility of gefitinib therapy in elderly patients with non-small-cell lung cancer is uncertain. This phase II study aimed to investigate the efficacy and usefulness of gefitinib therapy as a first-line treatment for elderly patients who have advanced lung adenocarcinoma with epidermal growth factor receptor (EGFR) mutations. PATIENTS AND METHODS: We enrolled chemotherapy-naïve advanced lung adenocarcinoma patients aged 75 years or older. Patients were administered gefitinib (250 mg) once daily until progression or unacceptable toxicity. The primary endpoint was response rate (RR), and secondary endpoints were disease control rate (DCR; defined as complete response [CR] plus partial response [PR] plus stable disease [SD]), progression-free survival (PFS), overall survival (OS), and toxicity profile. RESULTS: Between April 2008 and November 2009, 17 lung adenocarcinoma patients were enrolled. Overall RR was 59% (95% confidence interval [CI]: 33% to 81%), with 2 patients achieving CR and 8 PR. SD was noted in 5 patients, and DCR was 88% (95% CI: 62% to 98%). Median PFS was 12.9 months (95% CI: 2.2 to 23.6 months), and median OS had not yet been reached. Major grade 3 toxicities were skin rash (12%) and increased levels of aspartate aminotransferase or alanine aminotransferase (18%). CONCLUSION: First-line treatment with gefitinib was effective and well-tolerated in elderly patients with EGFR mutations.

Characterization of dense artificial connective tissues generated in a newly designed bioreactor.

Dense connective tissues were generated simultaneously by accumulating collagen fibrils and fibroblasts on stainless steel mesh using a bioreactor system that we designed. The advantage of our system is that the artificial connective tissues can be generated within 24 hr in the absence of inhibitors against matrix metalloproteinases. The fibroblasts were suspended in 200 mL of Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and 0.5 mg/mL type I collagen. The mixed solution was circulated in two types of bioreactors with cylindrical or vertical configurations to generate luminal or parenchymal tissues, respectively. The gelatin zymography showed that MMPs were first detected in the media after 8 hr from the start of circulation and reached the highest levels on day 3. Glossy white aggregates, 1-3 mm in thickness, depending on the circulation period, accumulated on mesh grids. Fibroblasts were embedded in the network of collagen fibrils and possessed oval nuclei with or without prominent cell processes to form a bipolar shape. We could not observe distended cisternae of the endoplasmic reticula, the Golgi apparatus, or exploded mitochondria, showing hypoxic degenerative alterations of fibroblasts in dense connective tissues. The artificial tissues generated by our system will be useful for biological studies and transplantation therapy.

Clinical experience of laparoscopy-assisted proximal gastrectomy with Toupet-like partial fundoplication in early gastric cancer for preventing reflux esophagitis.

BACKGROUND: Laparoscopy-assisted proximal gastrectomy (LAPG) has become prevalent for early gastric cancer in the upper stomach, but standard esophagogastrostomy is sometimes complicated with reflux esophagitis. Clinical outcomes are described here in patients with reconstruction by esophagogastrostomy with Toupet-like partial fundoplication (TPF) in LAPG. STUDY DESIGN: From November 2005 through December 2008, LAPG was performed in 36 patients with early gastric cancer, 26 (72.2%) of whom could have reconstruction with the TPF because the remnant stomach was sufficiently large. RESULTS: In LAPG with TPF, mean operation time was 293 minutes, mean blood loss was 119 g, and the mean number of dissected lymph nodes was 25.1. Regarding postoperative complications, anastomotic leakage occurred in two patients. More than 1 year after operation, 3 (15.0%) of the 20 patients had heartburn and 6 (30.0%) had reflux esophagitis (Los Angeles classification grade A, n=2; grade B, n=4); proton pump inhibitors were effective in these patients. CONCLUSIONS: Esophagogastrostomy with TPF could be a simple, safe, and useful technique for reconstruction after LAPG in patients with early gastric cancer, and its clinical usefulness is worthwhile for the prospective validation.

Laparoscopy-assisted pancreas- and spleen-preserving total gastrectomy for gastric cancer as compared with open total gastrectomy.

BACKGROUND: Laparoscopy-assisted total gastrectomy (LATG) is not widely used for the treatment of gastric cancer located in the upper or middle third of the stomach. To assess the safety and usefulness of LATG, we compared the outcomes of LATG with those of open total gastrectomy (OTG). METHODS: From July 2004 to July 2007, we performed pancreas- and spleen-preserving total gastrectomy with D1 + beta or D2 lymph-node dissection and Roux-en-Y reconstruction in 74 patients with cancer located in the upper or middle third of the stomach. Of these patients, 30 underwent LATG (LATG group) and 44 underwent OTG (OTG group). Short-term outcomes were compared between the groups. RESULTS: Operation time was significantly longer in the LATG group than in the OTG group (313 min vs. 218 min, p < 0.001). Blood loss (134 g vs. 407 g, p < 0.001) and the rate of the use of analgesics (6.8 times vs. 11.8 times, p < 0.05) were significantly lower, and postoperative hospital stay was significantly shorter in the LATG group than in the OTG group (13.5 days vs. 18.2 days, p < 0.05). The LATG group had better hematologic and serum chemical profiles, including white-cell counts, C-reactive protein levels, total protein levels, and albumin levels, as well as lower rate of postoperative body-weight loss. The number of dissected lymph nodes (43.2 vs. 51.2, p = 0.098) and the rate of postoperative complications (20.0% vs. 27.3%, p = 0.287) were similar in the groups. However, major complications such as anastomotic leakage, abdominal abscess, and pancreatic leakage occurred in six patients (13.6%) in the OTG group, but in none of the patients in the LATG group. CONCLUSIONS: LATG is associated with less severe complications and better postoperative quality of life than OTG. We believe that LATG is a safe, useful, and less invasive alternative for the treatment of gastric cancer located in the upper or middle third of the stomach.

Liver metastasis of colorectal cancer by protein-tyrosine phosphatase type 4A, 3 (PRL-3) is mediated through lymph node metastasis and elevated serum tumor markers such as CEA and CA19-9.

Phosphatase of regenerating liver (PRL)-3 was identified as a molecule associated with liver metastasis in colorectal cancer (CRC), although its precise causative role in distant metastasis remains elusive from a clinical point of view. The aim of this study was to promote the mechanistic insight of PRL-3 involvement in liver metastasis in CRC. One hundred and seven CRC patients with resection of the primary lesions were studied for clinicopathological and prognostic association with PRL-3 and were evaluated by immunohistochemistry in univariate and multivariate analyses. Intense immunostaining of PRL-3 was found in Dukes' A (0/26), Dukes' B (0/30), Dukes' C (18/30) and Duke's D (20/21) although the PRL-3 expression could not predict metachronous liver metastasis (MLM) in Dukes' C patients. PRL-3 expression showed an inverse correlation of prognosis in a univariate prognostic analysis (P<0.0001), though a multivariate assay failed to demonstrate PRL-3 relevance as an independent prognostic factor. PRL-3 expression was closely associated with classic prognostic factors such as the pN factor (P<0.0001), H factor-synchronous liver metastasis (SLM) (P<0.0001), pT factor (P=0.0002), preoperative CEA (P<0.0001) and preoperative CA19-9 (P<0.0001). Multivariate logistic regression analysis of PRL-3 expression revealed that the pN factor (P<0.0001), CEA (P<0.0001) and CA19-9 (P<0.0001) were finally remnant as an independent association with PRL-3. However, the H factor (SLM) was eliminated. Our data suggested that liver metastasis by PRL-3 is putatively mediated through lymph node metastasis and elevated tumor markers in the serum and the PRL-3 expression may not represent a direct causative mechanism of liver metastasis.

Silica-associated systemic lupus erythematosus in an elderly man.

The predominantly young woman-orientated systemic lupus erythematosus (SLE) is a disease that involves an extremely complicated and multifactorial interaction of various genetic and environmental factors. Crystalline silica (Si) may act as an immunoadjuvant to increase secretions of inflammatory endogenous substances and antibody production. In addition, previous studies have suggested that exposure to Si may induce SLE. Although the biologic mechanism of Si in SLE is unclear, defective apoptosis leading to the prolonged survival of pathogenic lymphocytes was thought to be one of mechanisms of Si-associated SLE (sSLE). In the present study, a rare case of an elderly man suffering from sSLE responded well to glucocorticoid therapy. The present findings were reviewed with reference to previous literature.

Immunohistochemical distribution of heat shock protein 47 (HSP47) in scirrhous carcinoma of the stomach.

BACKGROUND: The aim of the present study was to examine the immunohistochemical distribution of the 47-kDa heat shock protein (HSP47) to enhance the understanding of the mechanisms involved in stromal fibrosis, which accompanies cancer infiltration in scirrhous carcinoma of the stomach. MATERIALS AND METHODS: In vitro gastric cancer models were prepared by collagen gel cultures using three different human gastric cancer cell lines (KATO-III, MKN-74, MKN-45) and a human fibroblast cell line (TIG-101). Tumor tissues were obtained from ten patients with early gastric cancer (5 scirrhous carcinoma; 5 non-scirrhous carcinoma) and three patients with advanced scirrhous gastric cancer. The gels and the tissues were immunostained by a monoclonal antibody against human HSP47 and then examined by light and electron microscopy. RESULTS: The staining intensity of the fibroblasts was stronger than that of cancer cells in both the culture models and patient tissues. Moreover, the number of fibroblasts in scirrhous gastric cancer was significantly greater than that in non-scirrhous gastric cancer (p = 0.0004). In addition, the discharge of HSP47 was observed in the extracellular matrix as granular deposits of staining. CONCLUSION: These findings indicate that fibroblasts predominantly produce stromal collagen and may play an important role in the development of stromal change in scirrhous gastric cancer. Further studies are required to elucidate the significance of HSP47 in the development of new clinical approaches for treating scirrhous gastric cancer.

Phase II study of weekly docetaxel combined with cisplatin in patients with advanced non-small-cell lung cancer.

PURPOSE: To evaluate the safety and efficacy of the combination of cisplatin on day 1 and docetaxel on days 1, 8 and 15 every 4 weeks for the treatment of previously untreated patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: A group of 38 patients with advanced or metastatic NSCLC who had not received prior treatment and who were aged under 75 years were enrolled. The patients received intravenous infusions of docetaxel (25 mg/m2, days 1, 8, 15) and cisplatin (80 mg/m2, day 1), followed by a week of rest. RESULTS: Six patients had grade 3/4 neutropenia (18%), but there were no episodes of neutropenic fever. Nonhematologic toxicities were also mild. There were 12 partial responses for an objective response rate of 31.6%. The median survival was 11.8 months, and the 1-year survival rate was 46.5%. CONCLUSION: Cisplatin combined with weekly administration of docetaxel is efficacious against NSCLC with low hematotoxicity, and this schedule may be an alternative for the treatment of NSCLC.

Thermostability gradient in the collagen triple helix reveals its multi-domain structure.

A triple-helical conformation and stability at physiological temperature are critical for the mechanical and biological functions of the fibril-forming collagens. Here, we characterized the role of consecutive domains of collagen II in stabilizing the triple helix. Analysis of melting temperatures of genetically engineered collagen-like proteins consisting of tandem repeats of the D1, D2, D3 or D4 collagen II periods revealed the presence of a gradient of thermostability along the collagen molecule with thermolabile N-terminal domains and thermostable C-terminal domains. These results imply a multi-domain character of the collagen triple helix. Assays of thermostabilities of the Arg75Cys and Arg789Cys collagen II mutants suggest that, in contrast to the thermostable domains, the thermolabile domains are able to accommodate amino acid substitutions without altering the thermostability of the entire collagen molecule.

Role of endoscopic clipping for determining the resection line for tumors located in the middle or upper corpus of the stomach: experience with 100 gastrectomies for early gastric cancer.

BACKGROUND: The efficacy and limitations of preoperative endoscopic clipping for determining the resection line in patients with early gastric cancer remain unclear. MATERIALS AND METHODS: Subjects comprised 100 patients with early gastric cancer (33 females, 67 males; mean age, 60.5 years; range, 33-84 years) who underwent pre-operative endoscopic clipping for lesions located in the middle or upper corpus of the stomach. The results of endoscopic clipping for a selection of appropriate surgical procedures were investigated. RESULTS: Distal gastrectomy was performed in 94 patients, the mean length between the lesion and proximal surgical margin of the resected stomach being 28.9 +/- 18.0 mm (mean +/- SD). The surgical margin was eventually free of tumor in all patients. In 5 patients, clips were considered to be placed inadequately, and all 5 tumors were macroscopically depressed or flat and > 40 mm in size. CONCLUSION: Pre-operative endoscopic clipping represents a safe and reliable procedure to determine the resection line for tumors located in the middle or upper corpus of the stomach for treatment of early gastric cancer. During surgical resection, frozen section examination of the proximal cut end is recommended for patients with tumors that are macroscopically depressed or flat and > 40 mm in size, or that display a macroscopically unclear proximal margin.