Establishment of a novel overlay culture method that enables immune response assessment using gastric cancer organoids.

Organoid technology, a novel 3D cell culture system, can reproduce a patient's cancer and may be a novel immunotherapy experimental model. However, currently no gastric cancer organoid (GCO) models in which the organoid and immune cells are in free contact and sufficiently react with each other exist. In this study, we aimed to create a coculture model in which immune cells can move freely and stay in contact with GCOs. We coated the bottom surface of the plate with Matrigel and adhered stem cells to the Matrigel surface, instead of completely embedding them in Matrigel to culture organoids. This method allowed GCOs to grow on the Matrigel surface while maintaining a three-dimensional structure and reproducing the characteristics of the patient's cancer. We cocultured GCOs and immune cells. Using this model, immune cells could freely move and were in sufficient contact with the cultured GCOs. Our model allowed real-time observation of the immune response and tumor destruction with time. In addition, the GCO killing assay was assessed with natural killer cells from the same patient. This organoid culture model enabled repeated evaluation of the GCO killing assay with various immune cells in vitro. We established a new experimental model that allowed free movement of immune cells and sufficient contact with GCOs. Using this model, it may be possible to predict the effects of immune checkpoint inhibitors in vitro (using GCOs) before administering them to patients.

Assessment of Elastic Laminal Invasion Contributes to an Objective pT3 Subclassification in Colon Cancer.

The extent of tumor spread influences on the clinical outcome, and which determine T stage of colorectal cancer. However, pathologic discrimination between pT3 and pT4a in the eighth edition of the American Joint Committee on Cancer (AJCC)-TNM stage is subjective, and more objective discrimination method for deeply invasive advanced colon cancer is mandatory for standardized patient management. Peritoneal elastic laminal invasion (ELI) detected using elastic staining may increase the objective discrimination of deeply invasive advanced colon cancer. In this study, we constructed ELI study group to investigate feasibility, objectivity, and prognostic utility of ELI. Furthermore, pT classification using ELI was investigated based on these data. At first, concordance study investigated objectivity using 60 pT3 and pT4a colon cancers. Simultaneously, a multi-institutional retrospective study was performed to assess ELI's prognostic utility in 1202 colon cancer cases from 6 institutions. In the concordance study, objectivity, represented by κ, was higher in the ELI assessment than in pT classification. In the multi-institutional retrospective study, elastic staining revealed that ELI was a strong prognostic factor. The clinical outcome of pT3 cases with ELI was significantly and consistently worse than that of those without ELI. pT classification into pT3 without ELI, pT3 with ELI, and pT4a was an independent prognostic factor. In this study, we revealed that ELI is an objective method for discriminating deeply invasive advanced colon cancer. Based on its feasibility, objectivity, and prognostic utility, ELI can subdivide pT3 lesions into pT3a (without ELI) and pT3b (with ELI).

Assessment of postoperative common bile duct stones after endoscopic extraction and subsequent cholecystectomy.

BACKGROUND: Common bile duct stones (CBDSs) occasionally cause serious diseases, and endoscopic extraction is the standard procedure for CBDS. To prevent biliary complications, cholecystectomy is recommended for patients who present with gallbladder (GB) stones after endoscopic CBDS extraction. However, CBDS can occasionally recur. To date, the occurrence of CBDS after endoscopic CBDS extraction and subsequent cholecystectomy is not fully understood. Hence, the current study aimed to evaluate the incidence of postoperative CBDSs. METHODS: This retrospective observational study included consecutive patients who underwent postoperative endoscopic retrograde cholangiography after endoscopic CBDS extraction and subsequent cholecystectomy between April 2012 and June 2021 at our institution. After endoscopic CBDS extraction, a biliary plastic stent was inserted to prevent obstructive cholangitis. Endoscopic retrograde cholangiography was performed to evaluate postoperative CBDSs after cholecystectomy until hospital discharge. The outcomes were the incidence of postoperative CBDSs and CBDSs/sludge. Moreover, the predictive factors for postoperative CBDSs were evaluated via univariate and multivariate analyses. RESULTS: Of eligible 204 patients, 52 patients (25.5%) presented with postoperative CBDSs. The incidence rate of CBDS/sludge was 36.8% (n = 75). Based on the univariate analysis, the significant predictive factors for postoperative CBDSs were ≥ 6 CBDSs, presence of cystic duct stones, and ≥ 10 GB stones (P < 0.05). Moreover, male sex and < 60-mm minor axis in GB might be predictive factors (P < 0.10). Based on the multivariate analysis, ≥ 6 CBDSs (odds ratio = 6.65, P < 0.01), presence of cystic duct stones (odds ratio = 4.39, P < 0.01), and ≥ 10 GB stones (odds ratio = 2.55, P = 0.01) were independent predictive factors for postoperative CBDSs. CONCLUSIONS: The incidence of postoperative CBDS was relatively high. Hence, patients with predictive factors for postoperative CBDS must undergo imaging tests or additional endoscopic procedure after cholecystectomy.

First optical observation of 10B-neutron capture reactions using a boron-added liquid scintillator for quality assurance in boron neutron capture therapy.

10B-neutron capture was observed optically using a boron-added liquid scintillator. Trimethyl borate was dissolved in a commercially available liquid scintillator at natural boron concentrations of approximately 1 wt% and 0.25 wt%. The boron-added liquid scintillator was placed in a phantom quartz bottle and irradiated by thermal neutrons (~ 105 n/[cm2 s]) for 150, 300, and 600 s. The luminescence of the liquid scintillator was clearly observed using a cooled charge-coupled device (CCD) camera during irradiation. The luminance value recorded by the CCD camera was proportional to the duration of irradiation by thermal neutrons. The luminescence distribution showed reasonable agreement with that of energy deposition by Li and alpha particles from 10B-neutron capture reactions calculated via Monte Carlo simulations. When trimethyl borate was not dissolved in the liquid scintillator (0 wt% natural boron), no visible luminescence was observed even after 600 s of irradiation. These findings demonstrate that the observed luminance originates from the Li and alpha particles generated by 10B-neutron capture reactions. Consequently, the luminescence distribution is directly related to the boron dose of the liquid scintillator. To the best of our knowledge, direct experimental optical observations of boron dose distribution have not yet been reported. This novel technique will be useful for quality assurance in boron neutron capture therapy (BNCT) because instantaneous neutron irradiation may be sufficient for the observing the intense neutron beam used in clinical BNCT (~ 109 n/[cm2 s]), and quick evaluation of the boron dose distribution is expected to be feasible.

Risk assessment of metachronous squamous cell carcinoma after endoscopic resection for esophageal carcinoma based on the genetic polymorphisms of alcoholdehydrogense-1B aldehyde dehydrogenase-2: temperance reduces the risk.

BACKGROUND: Metachronous multiple squamous cell carcinoma (SCC) of the esophagus and the head and neck is commonly observed in patients who have previously undergone endoscopic resection (ER) for SCC of the esophagus (ESCC). We evaluated the risk for developing metachronous SCC following ER for ESCC based on the genetic polymorphisms for alcohol dehydrogenase-1B (ADH1B) and aldehyde dehydrogenase-2 (ALDH2) as well as the alcohol consumption and smoking habits. METHODS: We studied 158 patients who underwent ER for ESCC (median follow-up 80 months). Genotyping of ADH1B/ALDH2 was performed using saliva sampling. The alcohol consumption and smoking histories of the patients before and after the ER were documented. RESULTS: Multivariate analyses revealed that inactive heterozygous ALDH2 [hazard ratio (HR) 2.25] and alcohol consumption after ER (HR 1.94) were independently associated with the risk of developing secondary SCC. Moreover, inactive heterozygous ALDH2 (HR 4.39) and alcohol consumption after the ER (HR 2.82) were independently associated with the risk of a third SCC. We analyzed 110 patients who had a history of moderate or heavy alcohol consumption before the ER. The 3-year cumulative incidence rates of secondary SCC in the temperance (n = 65) and non-temperance groups (n = 45) were 14.0 and 42.1% (p = 0.0002). Further, the 5-year cumulative incidence rates of a third SCC in the temperance and non-temperance groups were 0 and 15.6% (p = 0.0011), respectively. In addition, the 7-year cumulative incidence rates of a fourth SCC in the temperance and non-temperance groups were 0 and 15.3% (p = 0.0015), respectively. CONCLUSIONS: Continued alcohol consumption is an important risk factor for the onset of metachronous SCC and is a risk factor for the third and subsequent SCCs. Strict advice in favor of temperance is crucial.

Roadmap to eliminate gastric cancer with Helicobacter pylori eradication and consecutive surveillance in Japan.

In Japan, the annual number of deaths from gastric cancer is approximately 50,000 and there has been no change over the last 50 years. So far, all efforts have been directed toward improving the detection of early gastric cancer by barium X-ray and endoscopy, since early cancer has a good prognosis, resulting in Japan having the best diagnostic capability for early gastric cancer worldwide. The 5-year survival rate of gastric cancer patients exceeds 60 % in Japan and is much higher than that in Europe and the US (20 %) because of this superior diagnosis of early gastric cancer. In February 2013, national health insurance coverage for Helicobacter pylori eradication therapy to treat H. pylori-associated chronic gastritis became available in Japan. H. pylori-associated gastritis leads to development of gastric and duodenal ulcers and gastric polyps. Therefore, providing treatment for gastritis is likely to substantially decrease the prevalence of both gastric and duodenal ulcers and polyps. Because treatment for H. pylori-associated gastritis, which leads to atrophic gastritis and gastric cancer, is now covered by health insurance in Japan, a strategy to eliminate gastric cancer-related deaths by taking advantage of this innovation was planned. According to this strategy, patients with gastritis will be investigated for H. pylori infection and those who are positive will receive eradication therapy followed by periodic surveillance. If this strategy is implemented, deaths from gastric cancer in Japan will decrease dramatically after 10-20 years.

Pretreatment prediction of anemia progression by pegylated interferon alpha-2b plus ribavirin combination therapy in chronic hepatitis C infection: decision-tree analysis.

BACKGROUND: This study aimed to develop a model to predict the development of severe anemia during pegylated interferon alpha-2b plus ribavirin combination therapy. METHODS: Data were collected from 1081 genotype 1b chronic hepatitis C patients who were treated at 6 hospitals in Japan. These patients were randomly assigned to a model-building group (n = 691) or an internal validation group (n = 390). Factors predictive of severe anemia (hemoglobin, Hb < 8.5 g/dl) were explored using data-mining analysis. RESULTS: Hb values at baseline, creatinine clearance (Ccr), and an Hb concentration decline by 2 g/dl at week 2 were used to build a decision-tree model, in which the patients were divided into 5 subgroups based on variable rates of severe anemia ranging from 0.4 to 11.8%. The reproducibility of the model was confirmed by the internal validation group (r² = 0.96). The probability of severe anemia was high in patients whose Hb value was <14 g/dl before treatment (6.5%), especially (a) in those whose Ccr was <80 ml/min (11.8%) and (b) those whose Ccr was ≥ 80 ml/min but whose Hb concentration decline at week 2 was ≥ 2 g/dl (11.5%). The probability of severe anemia was low in the other patients (0.4-2.5%). CONCLUSIONS: The decision-tree model that included Hb values at baseline, Ccr, and an Hb concentration decline by 2 g/dl at week 2 was useful for predicting the probability of severe anemia, and has the potential to support clinical decisions regarding early dose reduction of ribavirin.