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Background Spontaneous regression (SR) of cancer occurs in 1 in 60,000–100,000 patients. This phenomenon has been reported in almost all cancer types, most commonly neuroblastoma, renal cell carcinoma, malignant melanoma, and lymphoma/leukemia. However, SR in colorectal cancer (CRC) is extremely rare, particularly in advanced cases. Hence, this report describes a very rare case of spontaneous regression of advanced transverse colon cancer. Case presentation A 76-year-old female with anemia was diagnosed with a type II well-differentiated adenocarcinoma in the middle transverse colon. Two months later, a second colonoscopy examination was performed for preoperative marking, and it revealed tumor shrinkage and a shift to type 0–IIc morphology. Endoscopic tattooing was then performed, followed by a laparoscopic partial resection of the transverse colon with D3 lymph node dissection. However, the resected specimen contained no tumor, and colonoscopy showed no tumor remnants in the remaining colon. Histopathological examination revealed mucosal regeneration and a mucus nodule in between the submucosal and muscular layers, with no cancer cells detected. Immunohistochemical analysis revealed the loss of MutL homolog 1 (MLH1) and postmeiotic segregation increased 2 (PMS2) expression in the cancer cells of biopsied specimens, suggesting deficient mismatch repair (dMMR). The patient continues to be followed up until 6 years postoperatively, and no recurrence has been observed. In this study, we also reviewed similar reported cases of spontaneous regression of cancer involving dMMR. Conclusion This study presents a rare case of spontaneous regression of advanced transverse colon cancer wherein dMMR is strongly involved. However, further accumulation of similar cases is needed to elucidate this phenomenon and to develop new treatment strategies for CRC.

Background Cisplatin-induced acute kidney injury (AKI) is common during preoperative chemotherapy for esophageal cancer. The purpose of this study was to investigate the association between AKI after preoperative chemotherapy and postoperative complications in patients with esophageal cancer. Methods In this retrospective cohort study, we included patients who had received preoperative chemotherapy with cisplatin and underwent surgical resection for esophageal cancer under general anesthesia from January 2017 to February 2022 at an education hospital. A predictor was stage 2 or higher cisplatin-induced AKI (c-AKI) defined by the KDIGO criteria within 10 days after chemotherapy. Outcomes were postoperative complications and length of hospital stays. Associations between c-AKI and outcomes including postoperative complications and length of hospital stays were examined with logistic regression models. Results Among 101 subjects, 22 developed c-AKI with full recovery of the estimated glomerular filtration (eGFR) before surgery. Demographics were not significantly different between patients with and without c-AKI. Patients with c-AKI had significantly longer hospital stays than those without c-AKI [mean (95% confidence interval (95%CI)) 27.6 days (23.3–31.9) and 43.8 days (26.5–61.2), respectively, mean difference (95%CI) 16.2 days (4.4–28.1)]. Those with c-AKI had higher C-reactive protein (CRP) levels and prolonged weight gain after surgery and before the events of interest despite having comparable eGFR trajectories after surgery. c-AKI was significantly associated with anastomotic leakage and postoperative pneumonia [odds ratios (95%CI) 4.14 (1.30–13.18) and 3.87 (1.35–11.0), respectively]. Propensity score adjustment and inverse probability weighing yielded similar results. Mediation analysis showed that a higher incidence of anastomotic leakage in patients with c-AKI was primarily mediated by CRP levels (mediation percentage 48%). Conclusion c-AKI after preoperative chemotherapy in esophageal cancer patients was significantly associated with the development of postoperative complications and led to a resultant longer hospital stay. Increased vascular permeability and tissue edema due to prolonged inflammation might explain the mechanisms for the higher incidence of postoperative complications.

Background In gastrectomies, especially subtotal gastrectomies and operations on the gastroesophageal junction, identifying the exact location of the tumor and establishing the appropriate resection line is very important. Accurate resection lines have a major impact on the preservation of organ function and curability. Preservation of as much as possible of the remaining stomach, including the fornix, may be an important surgical goal for maintaining an adequate postoperative quality of life. In adenocarcinoma of the gastroesophageal junction, the height of the esophageal dissection may affect reconstruction of the transhiatal approach. Methods We perform a new technique, near infrared ray-guided surgery, for the accurate localization of a tumor using the Firefly technology of the daVinci Xi system and intra-operative upper gastrointestinal endoscopy. We used this new technique for cases of upper gastric cancer or adenocarcinoma of the gastroesophageal junction. In this retrospective study, we examined to determine the extent (mm) of the tumor invasion of the esophagus, visualization of near infrared ray contained within endoscopic light, and distance from the proximal margin of the tumor to the surgical cut line on rapid histopathology and in the permanent preparation, including the operative videos and extracted specimens. Results We performed near infrared ray-guided surgery for 12 patients with gastric cancer or adenocarcinoma of the gastroesophageal junction, and the near infrared ray was clearly seen as green light with Firefly mode in all the patients. Near infrared ray-guided surgery was useful for obtaining localization of the tumor. In addition, it was possible to resect organ with adequate margins from tumor. Rapid intraoperative histopathological examinations confirmed that the resected specimens had negative margins. None of the patients required additional resection. Conclusions We believe that because near infrared ray-guided surgery can provide an accurate resection line, it will be useful for the resection of upper gastric cancer and adenocarcinoma of the gastroesophageal junction. It will also provide patients with a good postoperative quality of life after surgery.

Few studies have investigated or verified the pressure resistance of anastomosis with circular staplers. We conducted end-to-end anastomoses with circular staplers and compared the pressure resistance with or without bioabsorbable material (Neoveil NanoⓇ). We conducted end-to-end anastomosis with or without Neoveil NanoⓇ (NN). Fresh pig small intestines were used. An end-to-end anastomosis was performed between two intestinal specimens using a circular stapler. The burst pressure of the anastomosis was recorded. The group with the highest pressure resistance was the group in which NN was attached only to the anvil, which was higher than the group in which NN was attached to the shaft and anvil. In contrast, no increase in pressure resistance occurred in the group using NN only for the shaft. Clinically, this method was used for various anastomoses using a circular stapler. In the absence of NN, a portion of the staple was often exposed at the anastomosis. When NN was used, however, only a small amount of the staple was exposed. There were no complications that were associated with NN. The usefulness of NN for pressure resistance of anastomosis with a circular stapler was demonstrated. The pressure resistance was highest by attaching NN only to the anvil of the stapler. Use of a circular stapler significantly reduces the complication associated with an anastomosis.

To develop novel therapeutic and diagnostic methods for esophageal cancer, it is important to understand the precise biological mechanism. Micro-RNAs (miRNAs) seem to be crucial factors in diverse regulation pathways. In this study, we analyzed the expression of mature miRNAs in esophageal squamous cell carcinoma (ESCC). The expression of 73 miRNAs was quantified by qRT-PCR in 30 primary ESCC specimens. We examined the correlation between miRNA expressions and the clinicopathological factors and prognosis of ESCC. The Kaplan-Meier survival curves showed that the high expression levels of 6 of the 72 miRNAs correlated with significantly lower patient survival rates. The overexpression of miR-129 was identified as a significant and independent prognostic factor (P = 0.031) in surgically treated ESCC patients. The hazard ratio for the prediction of early death was 18.11 for high versus low expression levels of miR-129. Similar results were obtained from an analysis performed on an additional 19 patients (test cohort) (P = 0.0057, for training cohort; P = 0.011, for test cohort; log-rank test). This experiment supports the notion that the high miR-129 expression levels, as observed in this study, might play a important role in the development of esophageal cancer.

A segment of the transverse colon can be used for gastric reconstruction after a total gastrectomy. This report presents the case of a 68-year-old woman with primary adenocarcinoma of the colon in a segment used for reconstruction after a total gastrectomy. The interposed colon developed colon carcinoma 9 years after the gastric reconstruction. The possibility of a primary carcinoma arising in a gastric colon interposition must be considered when employing the transverse colon as a gastric substitute.

With synchronously grown cells of an aerobic unicellular marine cyanobacterium Synechococcus sp. Miami BG 043511, changes in the activities of anoxygenic, nitrogenase-dependent hydrogen photoproduction and oxygen photoevolution were measured under non-growing hydrogen production conditions. Interestingly, synchronously grown cells, incubated in light under an argon atmosphere, exhibited cyclic changes in the activity of nitrogenase-catalyzed hydrogen production for approximately 20- to 25-h intervals. Cyclic photosynthetic oxygen production activity also appeared in approximately the same intervals. However, changes in hydrogen production and oxygen production activities were inversely correlated and temporally separated. Stepwise accumulation of hydrogen in closed vessels was also observed in approximately 24-h cycles in these non-growing cells. These observations in non-growing cells suggest that this unicellular aerobic, nitrogen-fixing cyanobacterium may have an endogenous system to control the exhibition of cyclic rhythms, in addition to the previously studied cell cycle-oriented system. Expression and switching between these two systems may be related to the sufficiency or insufficiency of nitrogen growth nutrients. The possibility of the existence of a common control factor of the two systems involving glycogen is also discussed.

Background The diagnosis of lymph node metastasis in esophageal cancer by the presence and number of metastatic lymph nodes is an extremely important prognostic factor. In addition, the indication of non-surgical therapy is gaining more attention. Vascular endothelial growth factor C (VEGF-C) is potentially lymphangiogenic and selectively induces hyperplasia of the lymphatic vasculature. In this study, we investigated the expression of VEGF-C and whether it correlated with various clinico-pathologic findings. Methods KYSE series of esophageal cancer cell lines and 106 patients with primary esophageal squamous cell carcinomas who had undergone radical esophagectomy were analyzed. VEGF-C mRNA expression was determined by quantitative RT-PCR. Results High expression of VEGF-C was detected in most of the KYSE cell lines, especially KYSE410, yet, in an esophageal normal epithelium cell line, Het-1A, VEGF-C was not detected. In the clinical specimen, the expression of VEGF-C in the cancerous tissue was higher than in the corresponding noncancerous esophageal mucosa (p = 0.026). The expression of VEGF-C was found to be higher in Stage2B-4A tumors than in Stage0-2A tumors (p = 0.049). When the patients were divided into two groups according to their expression levels of VEGF-C (a group of 53 cases with high expression and a group of 53 cases with low expression), the patients with high VEGF-C expression had significantly shorter survival after surgery than the patients with low expression (p = 0.0065). Although univariate analysis showed that high expression of VEGF-C was a statistically significant prognostic factor, this was not shown in multivariate analysis. In the subgroup of patients with Tis and T1 tumors, the expression of VEGF-C was higher in N1 tumors than in N0 tumors (p = 0.029). The survival rate of patients from the high expression group (n = 10) was lower than that in the low expression group (n = 11), and all the patients in the low VEGF-C expression group survived. Conclusions The expression of VEGF-C correlates with lymph node metastasis and poor prognosis. In patients with Tis and T1 esophageal tumors, the expression of VEGF-C may be a good diagnostic factor for determining metastasis of the lymph node.

Synchronously growing cells of nitrogen-fixing Synechococcus sp. Miami BG 043511 were harvested periodically and the capability for hydrogen photoproduction in closed vessels was measured under hydrogen production conditions. The capability for hydrogen photoproduction in cells was correlated with that of cellular carbohydrate content. Cells with a high carbohydrate content exhibited a high capacity for hydrogen production and those with low carbohydrate content exhibited low capacity for hydrogen production. Nitrogenase activity at the onset of incubation did not coincide with a capability for the cells to produce hydrogen during the subsequent incubation period. Interestingly, when cells with a high capacity for hydrogen photoaccumulation were incubated, alternate periods of hydrogen and oxygen accumulation were observed at 12 hour intervals. About 0.5 ml of hydrogen per ml of cell suspension was accumulated in flasks during the initial 12-h incubation period. These observations indicate that the use of synchronous culture can be one of the ways of provide materials suitable not only for basic studies but also for applied aspects of hydrogen photoproduction.

The aerobic synchronous growth of marine unicellular cyanobacteriaSynechococcus spp., with molecular nitrogen as the sole nitrogen growth nutrient source, was experimentally demonstrated. Cell division synchrony was induced by withholding aeration and illumination for 20 h. Three distinct cell division cycles of approximately 20 h each were observed. During the first cell division cycle, high degrees of synchrony of 78%–86% were observed in the series of cultures studied. The aerobic nitrogenase activity appeared shortly while the cell division was completed and the cell size was still small, and it disappeared after the cells were enlarging photosynthetically. Thus, three distinct cycles in aerobic nitrogenase activity were also observed having approximately the same 20-h interval as the cell division cycle. The peak aerobic nitrogenase activity was determined to be as high as 840–1220 nmol C2H2 reduced per milligram dry weight per hour.

Among nitrogen-fixing microorganisms, nitrogen-fixing cyanobacteria are unique in their ability to carry out oxygen-evolving photosynthesis and oxygen-labile nitrogen fixation within the same organisms1–3. These seemingly incompatible reactions take place in heterocystous cyanobacteria by the spatial separation of the site of nitrogen fixation (heterocysts) from the site of photosynthesis (vegetative cells)4,5. Several hypotheses have been proposed to explain these mechanisms in non-heterocystous cyanobacteria3,6–11. Using batch cultures of Gloeothece (Gloeocapsa) spp., Gallon and collaborators demonstrated the mechanism of temporal separation of photosynthesis and nitrogen fixation into the light and dark periods of growth, respectively9. However, the mechanisms by which these two incompatible reactions can occur under continuous light conditions still remained ambiguous. Using novel strains of aerobic nitrogen-fixing, unicellular marine cyanobacteria, Synechococcus spp., grown under synchronized conditions, we report here that nitrogen fixation and photosynthesis occur at different phases in the cell division cycle. Our data, obtained under both diurnal light/dark cycle and continuous illumination, indicate that the temporal separation of the two phases during the cell division cycle is the mechanism by which these unicells can grow photoautotrophically under nitrogen-fixing conditions.