Circulating cell-free DNA methylation patterns as non-invasive biomarkers to monitor colorectal cancer treatment efficacy without referencing primary site mutation profiles.

This study investigates methylation patterns in circulating cell-free DNA (ccfDNA) for their potential role in colorectal cancer (CRC) detection and the monitoring of treatment response. Through methylation microarrays and quantitative PCR assays, we analyzed 440 samples from The Cancer Genome Atlas (TCGA) and an additional 949 CRC samples. We detected partial or extensive methylation in over 85% of cases within three biomarkers: EFEMP1, SFRP2, and UNC5C. A methylation score for at least one of the six candidate regions within these genes' promoters was present in over 95% of CRC cases, suggesting a viable detection method. In evaluating ccfDNA from 97 CRC patients and 62 control subjects, a difference in methylation and recovery signatures was observed. The combined score, integrating both methylation and recovery metrics, showed high diagnostic accuracy, evidenced by an area under the ROC curve of 0.90 (95% CI = 0.86 to 0.94). While correlating with tumor burden, this score gave early insight into disease progression in a small patient cohort. Our results suggest that DNA methylation in ccfDNA could serve as a sensitive biomarker for CRC, offering a less invasive and potentially more cost-effective approach to augment existing cancer detection and monitoring modalities, possibly supporting comprehensive genetic mutation profiling.

Overcoming immunotherapy resistance and inducing abscopal effects with boron neutron immunotherapy (B-NIT).

Immune checkpoint inhibitors (ICIs) are effective against many advanced malignancies. However, many patients are nonresponders to immunotherapy, and overcoming this resistance to treatment is important. Boron neutron capture therapy (BNCT) is a local chemoradiation therapy with the combination of boron drugs that accumulate selectively in cancer and the neutron irradiation of the cancer site. Here, we report the first boron neutron immunotherapy (B-NIT), combining BNCT and ICI immunotherapy, which was performed on a radioresistant and immunotherapy-resistant advanced-stage B16F10 melanoma mouse model. The BNCT group showed localized tumor suppression, but the anti-PD-1 antibody immunotherapy group did not show tumor suppression. Only the B-NIT group showed strong tumor growth inhibition at both BNCT-treated and shielded distant sites. Intratumoral CD8+ T-cell infiltration and serum high mobility group box 1 (HMGB1) levels were higher in the B-NIT group. Analysis of CD8+ T cells in tumor-infiltrating lymphocytes (TILs) showed that CD62L- CD44+ effector memory T cells and CD69+ early-activated T cells were predominantly increased in the B-NIT group. Administration of CD8-depleting mAb to the B-NIT group completely suppressed the augmented therapeutic effects. This indicated that B-NIT has a potent immune-induced abscopal effect, directly destroying tumors with BNCT, inducing antigen-spreading effects, and protecting normal tissue. B-NIT, immunotherapy combined with BNCT, is the first treatment to overcome immunotherapy resistance in malignant melanoma. In the future, as its therapeutic efficacy is demonstrated not only in melanoma but also in other immunotherapy-resistant malignancies, B-NIT can become a new treatment candidate for advanced-stage cancers.

Fibroblast activation protein-targeted near-infrared photoimmunotherapy depletes immunosuppressive cancer-associated fibroblasts and remodels local tumor immunity.

BACKGROUND: Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) play a critical role in tumor immunosuppression. However, targeted depletion of CAFs is difficult due to their diverse cells of origin and the resulting lack of specific surface markers. Near-infrared photoimmunotherapy (NIR-PIT) is a novel cancer treatment that leads to rapid cell membrane damage. METHODS: In this study, we used anti-mouse fibroblast activation protein (FAP) antibody to target FAP+ CAFs (FAP-targeted NIR-PIT) and investigated whether this therapy could suppress tumor progression and improve tumor immunity. RESULTS: FAP-targeted NIR-PIT induced specific cell death in CAFs without damaging adjacent normal cells. Furthermore, FAP-targeted NIR-PIT treated mice showed significant tumor regression in the CAF-rich tumor model accompanied by an increase in CD8+ tumor infiltrating lymphocytes (TILs). Moreover, treated tumors showed increased levels of IFN-γ, TNF-α, and IL-2 in CD8+ TILs compared with non-treated tumors, suggesting enhanced antitumor immunity. CONCLUSIONS: Cancers with FAP-positive CAFs in their TME grow rapidly and FAP-targeted NIR-PIT not only suppresses their growth but improves tumor immunosuppression. Thus, FAP-targeted NIR-PIT is a potential therapeutic strategy for selectively targeting the TME of CAF+ tumors.

Long-term activation of anti-tumor immunity in pancreatic cancer by a p53-expressing telomerase-specific oncolytic adenovirus.

BACKGROUND: Pancreatic cancer is an aggressive, immunologically "cold" tumor. Oncolytic virotherapy is a promising treatment to overcome this problem. We developed a telomerase-specific oncolytic adenovirus armed with p53 gene (OBP-702). METHODS: We investigated the efficacy of OBP-702 for pancreatic cancer, focusing on its long-term effects via long-lived memory CD8 + T cells including tissue-resident memory T cells (TRMs) and effector memory T cells (TEMs) differentiated from effector memory precursor cells (TEMps). RESULTS: First, in vitro, OBP-702 significantly induced adenosine triphosphate (ATP), which is important for memory T cell establishment. Next, in vivo, OBP-702 local treatment to murine pancreatic PAN02 tumors increased TEMps via ATP induction from tumors and IL-15Rα induction from macrophages, leading to TRM and TEM induction. Activation of these memory T cells by OBP-702 was also maintained in combination with gemcitabine+nab-paclitaxel (GN) in a PAN02 bilateral tumor model, and GN + OBP-702 showed significant anti-tumor effects and increased TRMs in OBP-702-uninjected tumors. Finally, in a neoadjuvant model, in which PAN02 cells were re-inoculated after resection of treated-PAN02 tumors, GN + OBP-702 provided long-term anti-tumor effects even after tumor resection. CONCLUSION: OBP-702 can be a long-term immunostimulant with sustained anti-tumor effects on immunologically cold pancreatic cancer.

Robotic Pancreatoduodenectomy in Portal Annular Pancreas Using a Hanging Maneuver with Indocyanine Green Fluorescence Imaging.

BACKGROUND: Sufficient knowledge and surgical management of portal annular pancreas (PAP) are essential for pancreatic surgery. As PAP is a relatively rare pancreatic anomaly, few studies have described surgical techniques for patients with PAP undergoing robotic pancreatoduodenectomy (RPD). PATIENTS AND METHODS: An 82-year-old female patient who underwent RPD presented with distal cholangiocarcinoma and type III PAP (the fusion of the uncinate process with the anteportal main pancreatic duct). After the Kocher maneuver and stomach transection, the pancreas was transected into the neck of the anteportal portion. The retroportal portion was dissected, encircled with hanging tape, and compressed. Blood supply from the mesenteric vessels was confirmed using indocyanine green (ICG) fluorescence imaging. Subsequently, the retroportal portion was stapled. CONCLUSIONS: This study demonstrates a unique surgical technique for type III PAP using the hanging maneuver with ICG fluorescence imaging. Surgeons should decide on the surgical strategy on the basis of the fusion and ductal anatomy of the pancreas.

Robot-Assisted Pancreaticoduodenectomy Using the Anterior Superior Mesenteric Artery-First Approach for Pancreatic Cancer.

BACKGROUND: The superior mesenteric artery (SMA)-first approach for pancreatic cancer (PC) is common surgical technique in pancreaticoduodenectomy. To date, few studies have reported SMA-first approach in robot-assisted pancreaticoduodenectomy (RPD). Herein, we present the anterior SMA-first approach for PC during RPD. PATIENT AND METHOD: A 75-year-old man with resectable PC underwent RPD after neoadjuvant chemotherapy. As pancreatic head tumor contacted with the superior mesenteric vein (SMV), the anterior SMA approach was applied. After the mesenteric Kocher maneuver, the jejunum was divided and the left side of the SMA was dissected. Subsequently, the anterior plane of the SMA was dissected. Following the division of branches from the mesenteric vessels, the SMA was taped, and the circumferential dissection around the SMA was performed to detach the pancreatic neck from the SMA completely. Finally, the dissection between the SMV and the tumor was performed under vascular control to remove the specimen. CONCLUSIONS: The anterior SMA-first approach can be optional in patients with PC undergoing RPD. This unique approach allows for the circumferential dissection around the SMA during RPD.

Perioperative and Postoperative Continuous Nutritional Counseling Improves Quality of Life of Gastric Cancer Patient Undergoing Gastrectomy.

Post-gastrectomy syndrome (PGS) and body weight loss (BWL) decrease quality of life (QOL) and survival of the patient undergoing gastrectomy. We have introduced perioperative and post-discharge continuous nutritional counseling (CNC) to prevent BWL and improve QOL after gastrectomy. In the present study, we evaluated the effect of CNC on QOL using the Post-gastrectomy Syndrome Assessment Scale-45 (PGSAS-45). Eighty-three patients with gastric cancer (GC) who underwent curative gastrectomy between March 2018 and July 2019 were retrospectively analyzed. Patients received either pre-discharge nutritional counseling alone (control group, n = 45) or CNC (CNC group, n = 38) after gastrectomy. QOL at 12 months after gastrectomy was compared between the two groups. In QOL assessment, change in body weight (-7.98% vs. -12.77%, p = 0.0057), ingested amount of food per meal (7.00 vs. 6.07, p = 0.042) and ability for working (1.89 vs. 2.36, p = 0.049) were significantly better in CNC group than control group. Multiple regression analysis showed that CNC was a significantly beneficial factor for abdominal pain subscale (p = 0.028), diarrhea subscale (p = 0.047), ingested amount of food per meal (p = 0.012), Ability for working (p = 0.031) and dissatisfaction at the meal (p = 0.047). Perioperative and postoperative CNC could improve QOL in the patient undergoing gastrectomy in addition to preventing postoperative BWL.

Risk model for predicting failure to rescue after hepatectomy: Cohort study of 1371 consecutive patients.

AIM: Although hepatectomy is a complex surgical procedure, its incidence among older patients has increased due to global aging. However, few studies have focused on the association between age and failure to rescue (FTR) posthepatectomy. This study aimed to investigate the association between age and FTR and develop a risk model for FTR following hepatectomy. METHODS: We analyzed a total of 1371 consecutive patients who underwent primary hepatectomy between July 2003 and September 2022. The patients were divided into three groups according to their age: young-old (<65 years), pre-old (65-74 years), and old group (≥75 years). Additionally, the associations among age, FTR, and risk factors for FTR were investigated. Subsequently, a risk model was developed to predict the FTR. RESULTS: Of the 1371 patients, 373 (27.2%) experienced major complications, and FTR occurred in 15 patients. The older group showed a higher FTR rate (8.4%) than the young-old (1.3%) and pre-old (4.3%) groups (p = 0.03). Multivariate analyses indicated that older age (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.00-1.15; p = 0.045) and American Society of Anesthesiologists Physical Status score ≥3 (OR 4.35; 95% CI 1.24-15.2; p = 0.02) were independent predictive factors for FTR. The risk model exhibited an accuracy with an area under the curve of 0.80 (95% CI 0.69-0.92). Calibration plots of the model revealed a concordance index of 0.73. CONCLUSIONS: This study identified an association between age, FTR, and risk factors for FTR posthepatectomy. Together, our risk model is a clinically relevant, internally validated, and useful tool for predicting FTR posthepatectomy.

Laparoscopic Resection Combined with a Transsacral Approach for a Recurrent Tailgut Cyst with a Refractory Fistula.

Tailgut cyst is a rare cystic disease of the anterior sacral surface and the remains of an embryonic tail gut. Tailgut cysts have a potential for malignancy, and complete resection with an adequate surgical margin is necessary. Even if incomplete resection does not result in recurrence of malignant disease, there is a risk of local infection leading to refractory fistulas. The optimal treatment for such refractory recurrent lesions has not been reported. We describe a case in which the combination of laparoscopic and transsacral approaches was effective for resecting a recurrent refractory fistula after incomplete resection of a tail gut cyst.

Perineal Squamous Cell Carcinoma Arising in an Epidermal Cyst.

A 90-year-old Japanese woman who had been aware of a subcutaneous mass on the right perineal region for 5 years was referred to our hospital for further examination and treatment because of the rapid growth of the mass and bleeding that began 3 months earlier. A biopsy of the mass revealed a diagnosis of well-differentiated squamous cell carcinoma. On preoperative examination, the tumor was 90×40 mm in size and was suspected to have partially invaded the levator ani muscle and external sphincter. Since a preoperative cardiac evaluation indicated severe aortic stenosis, we performed transcatheter aortic valve implantation. A radical resection was then performed with general anesthesia. The skin and subcutaneous tissue defects were reconstructed with a posterior gluteal-thigh propeller flap, and a sigmoid colostomy was created. The patient had a good postoperative course and was transferred to a rehabilitation facility 28 days after the surgery. Epidermal cysts are a common benign tumor, and clinicians should keep in mind that these cysts can become malignant.

p53-Armed Oncolytic Virotherapy Improves Radiosensitivity in Soft-Tissue Sarcoma by Suppressing BCL-xL Expression.

Soft-tissue sarcoma (STS) is a heterogeneous group of rare tumors originating predominantly from the embryonic mesoderm. Despite the development of combined modalities including radiotherapy, STSs are often refractory to antitumor modalities, and novel strategies that improve the prognosis of STS patients are needed. We previously demonstrated the therapeutic potential of two telomerase-specific replication-competent oncolytic adenoviruses, OBP-301 and tumor suppressor p53-armed OBP-702, in human STS cells. Here, we demonstrate in vitro and in vivo antitumor effects of OBP-702 in combination with ionizing radiation against human STS cells (HT1080, NMS-2, SYO-1). OBP-702 synergistically promoted the antitumor effect of ionizing radiation in the STS cells by suppressing the expression of B-cell lymphoma-X large (BCL-xL) and enhancing ionizing radiation-induced apoptosis. The in vivo experiments demonstrated that this combination therapy significantly suppressed STS tumors' growth. Our results suggest that OBP-702 is a promising antitumor reagent for promoting the radiosensitivity of STS tumors.

[PD-L1-Expressing Cancer-Associated Fibroblasts Have the Potential of a Biomarker for Immune Checkpoint Inhibitors].

Programmed cell death 1(PD-1)/programmed cell death ligand 1(PD-L1)axis is well known as the system resulting in the inhibition of immune responses and promotion of self-tolerance. The clinical indications for immune checkpoint inhibitors( ICIs), including the targeting of PD-1/PD-L1 axis, are dramatically expanding. However, since ICIs have been found to be ineffective or resistant in some types of cancer, the development of more effective combination therapies or predictors and biomarkers of efficacy are expected. On the other hand, we have been focusing on the tumor microenvironment(TME)as a therapeutic target, and have been analyzing the function of cancer-associated fibroblasts(CAFs), which play a central role in TME. Recently, CAFs are known to induce tumors to an immunosuppressive state, suggesting that ICIs may not be effective in such a cancer microenvironment. In this review, we demonstrated the impact of PD-L1 positivity in cancer cells and CAFs by immunohistochemistry for resected specimens. In addition, we evaluated the potential of PD-L1-positve CAFs for therapeutic target and biomarker for ICIs.

Oncolytic virus-mediated reducing of myeloid-derived suppressor cells enhances the efficacy of PD-L1 blockade in gemcitabine-resistant pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is often refractory to treatment with gemcitabine (GEM) and immune checkpoint inhibitors including anti-programmed cell death ligand 1 (PD-L1) antibody. However, the precise relationship between GEM-resistant PDAC and development of an immunosuppressive tumor microenvironment (TME) remains unclear. In this study, we investigated the immunosuppressive TME in parental and GEM-resistant PDAC tumors and assessed the therapeutic potential of combination therapy with the telomerase-specific replication-competent oncolytic adenovirus OBP-702, which induces tumor suppressor p53 protein and PD-L1 blockade against GEM-resistant PDAC tumors. Mouse PDAC cells (PAN02) and human PDAC cells (MIA PaCa-2, BxPC-3) were used to establish GEM-resistant PDAC lines. PD-L1 expression and the immunosuppressive TME were analyzed using parental and GEM-resistant PDAC cells. A cytokine array was used to investigate the underlying mechanism of immunosuppressive TME induction by GEM-resistant PAN02 cells. The GEM-resistant PAN02 tumor model was used to evaluate the antitumor effect of combination therapy with OBP-702 and PD-L1 blockade. GEM-resistant PDAC cells exhibited higher PD-L1 expression and produced higher granulocyte-macrophage colony-stimulating factor (GM-CSF) levels compared with parental cells, inducing an immunosuppressive TME and the accumulation of myeloid-derived suppressor cells (MDSCs). OBP-702 significantly inhibited GEM-resistant PAN02 tumor growth by suppressing GM-CSF-mediated MDSC accumulation. Moreover, combination treatment with OBP-702 significantly enhanced the antitumor efficacy of PD-L1 blockade against GEM-resistant PAN02 tumors. The present results suggest that combination therapy involving OBP-702 and PD-L1 blockade is a promising antitumor strategy for treating GEM-resistant PDAC with GM-CSF-induced immunosuppressive TME formation.

PD-L1-expressing cancer-associated fibroblasts induce tumor immunosuppression and contribute to poor clinical outcome in esophageal cancer.

The programmed cell death 1 protein (PD-1)/programmed cell death ligand 1 (PD-L1) axis plays a crucial role in tumor immunosuppression, while the cancer-associated fibroblasts (CAFs) have various tumor-promoting functions. To determine the advantage of immunotherapy, the relationship between the cancer cells and the CAFs was evaluated in terms of the PD-1/PD-L1 axis. Overall, 140 cases of esophageal cancer underwent an immunohistochemical analysis of the PD-L1 expression and its association with the expression of the α smooth muscle actin, fibroblast activation protein, CD8, and forkhead box P3 (FoxP3) positive cells. The relationship between the cancer cells and the CAFs was evaluated in vitro, and the effect of the anti-PD-L1 antibody was evaluated using a syngeneic mouse model. A survival analysis showed that the PD-L1+ CAF group had worse survival than the PD-L1- group. In vitro and in vivo, direct interaction between the cancer cells and the CAFs showed a mutually upregulated PD-L1 expression. In vivo, the anti-PD-L1 antibody increased the number of dead CAFs and cancer cells, resulting in increased CD8+ T cells and decreased FoxP3+ regulatory T cells. We demonstrated that the PD-L1-expressing CAFs lead to poor outcomes in patients with esophageal cancer. The cancer cells and the CAFs mutually enhanced the PD-L1 expression and induced tumor immunosuppression. Therefore, the PD-L1-expressing CAFs may be good targets for cancer therapy, inhibiting tumor progression and improving host tumor immunity.

Overcoming cancer-associated fibroblast-induced immunosuppression by anti-interleukin-6 receptor antibody.

Cancer-associated fibroblasts (CAFs) are a critical component of the tumor microenvironment and play a central role in tumor progression. Previously, we reported that CAFs might induce tumor immunosuppression via interleukin-6 (IL-6) and promote tumor progression by blocking local IL-6 in the tumor microenvironment with neutralizing antibody. Here, we explore whether an anti-IL-6 receptor antibody could be used as systemic therapy to treat cancer, and further investigate the mechanisms by which IL-6 induces tumor immunosuppression. In clinical samples, IL-6 expression was significantly correlated with α-smooth muscle actin expression, and high IL-6 cases showed tumor immunosuppression. Multivariate analysis showed that IL-6 expression was an independent prognostic factor. In vitro, IL-6 contributed to cell proliferation and differentiation into CAFs. Moreover, IL-6 increased hypoxia-inducible factor 1α (HIF1α) expression and induced tumor immunosuppression by enhancing glucose uptake by cancer cells and competing for glucose with immune cells. MR16-1, a rodent analog of anti-IL-6 receptor antibody, overcame CAF-induced immunosuppression and suppressed tumor progression in immunocompetent murine cancer models by regulating HIF1α activation in vivo. The anti-IL-6 receptor antibody could be systemically employed to overcome tumor immunosuppression and improve patient survival with various cancers. Furthermore, the tumor immunosuppression was suggested to be induced by IL-6 via HIF1α activation.

Effect of Patient-Participation Continuous Nutritional Counseling in Gastric Cancer Patients who Underwent Gastrectomy.

BACKGROUND: Body weight loss (BWL) and skeletal muscle loss (SML) are inevitable after gastrectomy for gastric cancer (GC) and can decrease patients' quality of life (QOL) and survival. OBJECTIVE: The aim of this retrospective study was to evaluate the effect of perioperative and post-discharge patient participation in continuous nutritional counseling (CNC) on post-gastrectomy BWL and SML. METHODS: Ninety-three patients with GC who underwent curative gastrectomy between March 2018 and July 2019 were analyzed. Patients received either pre-discharge nutritional counseling alone (control group, n = 49) or patient-participation CNC (CNC group, n = 44) after gastrectomy. Differences between percentage BWL (%BWL), percentage SML (%SML), and nutrition-related blood parameters between the preoperative values and those at 12 months after surgery were compared between the groups. RESULTS: Compared with the control group, %BWL was significantly lower in the CNC group at 1 month (-6.2 ± 2.5% vs. -7.9 ± 3.3%, p = 0.005), 6 months (-7.8 ± 6.6% vs. -12.3 ± 6.4%, p = 0.001) and 12 months (-7.9 ± 7.6% vs. -13.2 ± 8.2%, p = 0.002), and %SML was significantly lower in the CNC group at 12 months (-5.3 ± 10.3% vs. -12.8 ± 12%, p = 0.002). Regarding nutrition-related blood parameters, change in total cholesterol was significantly lower in the CNC group than the control group at 12 months after surgery (p = 0.02). Multivariate analysis identified no CNC as an independent risk factor for severe BWL (p = 0.001) and SML (p = 0.006) at 12 months after surgery. CONCLUSIONS: Following gastrectomy, patient-participation CNC prevented postoperative BWL and SML after surgery. These results support the induction of such a CNC program in these patients.

Incidence of Metachronous Remnant Gastric Cancer after Proximal Gastrectomy with the Double-flap Technique (rD-FLAP-rGC Study): A Multicenter, Retrospective Study.

BACKGROUND: Although proximal gastrectomy (PG) with the double-flap technique (DFT) is a function-preserving surgery that prevents esophagogastric reflux, there is a risk of developing metachronous remnant gastric cancer (MRGC). Moreover, details of MRGC and appropriate postoperative follow-up after PG with DFT are unclear. METHODS: We reviewed the medical records of 471 patients who underwent PG with DFT for cancer in a preceding, multicenter, retrospective study (rD-FLAP Study). We investigated the incidence of MRGC, frequency of follow-up endoscopy, and eradication of Helicobacter pylori (H. pylori) infection. RESULTS: MRGC was diagnosed in 42 (8.9%) of the 471 patients, and 56 lesions of MRGC were observed. The cumulative 5- and 10-year incidence rates were 5.7 and 11.4%, respectively. There was no clinicopathological difference at the time of primary PG between patients with and without MRGC. Curative resection for MRGC was performed for 49 (88%) lesions. All patients with a 1-year, follow-up, endoscopy interval were diagnosed with early-stage MRGC, and none of them died due to MRGC. Overall and disease-specific survival rates did not significantly differ between patients with and without MRGC. The incidence rate of MRGC in the eradicated group after PG was 10.8% and that in the uneradicated group was 19.6%, which was significantly higher than that in patients without H. pylori infection at primary PG (7.6%) (p = 0.049). CONCLUSIONS: The incidence rate of MRGC after PG with DFT was 8.9%. Early detection of MRGC with annual endoscopy provides survival benefits. Eradicating H. pylori infection can reduce the incidence of MRGC.

Genomically Stable Gastric Cancer Characterized by Hypomethylation in Wnt Signal Cascade.

INTRODUCTION: Gastric cancer is divided into four subtypes by their molecular features linked with genetic alterations, e.g., Epstein-Barr virus (EBV), microsatellite instability-high (MSI-high), chromosomal instability (CIN), and genomically stable (GS), called as TCGA classification. In this study, we tried to clarify the epigenetic features of the four GC subtypes according to aberrant methylation status in 23 loci. METHODS: A total of 98 gastric cancers and their normal gastric mucosa samples were included in this study. We divided gastric cancers into TCGA subtypes which were determined in line with MSI-high, EBV, CIN, to GS by their molecular features. The 13 loci of polymorphic microsatellite sequences were used to determine loss of heterogeneity for the detection of CIN. The MSI status was determined by three mononucleotide repeat markers. Infection of EBV was determined by recovering EBV BNRF1 sequence from genomic DNA collected from gastric cancers. Methylation status of 23 loci was investigated by the combined bisulfite restriction analysis. Status of other findings, e.g., KRAS mutations, HER2 expression status, and infection of helicobacter pylori were confirmed. RESULTS: Gastric cancers were divided into MSI (13%), EBV (7%), CIN (53%), and GS (27%). By histological classification, poorly differentiated adenocarcinoma was more in tumors categorized in MSI-high, and GS and signet-ring cell carcinoma (sig) were more in GS. Among the 23 loci investigated their methylation status, 18 loci were significantly hypermethylated in caner tissues. An unsupervised clustering divided gastric cancers into two clusters and revealed that most GS tumors clustered together in a cluster that exhibited lower methylation levels, distinct from the other subtypes. The inter-variable clustering revealed that a cluster contained the three loci (SFRP2-region 1/2 and APC) belonging to the Wnt signal cascade (Wnt-associated loci). The mean methylation score of Wnt-associated loci was the lowest in GS tumors (MSI-high: 2.7 [95% confidence interval, 2.3-2.9]; EBV: 2.1 [1.2-3.1]; CIN: 2.4 [2.2-2.7]; GS: 1.3 [0.8-0.7]). In contrast, the mean methylation score of the other 15 loci was significantly higher in MSI-high, while that in GS was as same as that in EBV or CIN (MSI-high: 10.4 [8.3-12.4]; EBV: 5.7 [1.7-9.7]; CIN: 4.4 [3.6-5.1]; GS: 3.4 [2.2-4.6]). Additionally, the lower methylation score of Wnt-associated loci was observed only in sig tumors. CONCLUSIONS: GS subtype tumors have the potential to possess distinct signatures in DNA hypomethylation profiles in Wnt signaling pathway, especially in sig.

Innovative suture technique for robotic hepaticojejunostomy: double-layer interrupted sutures.

PURPOSE: Biliary reconstruction remains a technically demanding and complicated procedure in minimally invasive hepatopancreatobiliary surgeries. No optimal hepaticojejunostomy (HJ) technique has been demonstrated to be superior for preventing biliary complications. This study aimed to investigate the feasibility of our unique technique of posterior double-layer interrupted sutures in robotic HJ. METHODS: We performed a retrospective analysis of a prospectively collected database. Forty-two patients who underwent robotic pancreatoduodenectomy using this technique between September 2020 and November 2022 at our center were reviewed. In the posterior double-layer interrupted technique, sutures were placed to bite the bile duct, posterior seromuscular layer of the jejunum, and full thickness of the jejunum. RESULTS: The median operative time was 410 (interquartile range [IQR], 388-478) min, and the median HJ time was 30 (IQR, 28-39) min. The median bile duct diameter was 7 (IQR, 6-10) mm. Of the 42 patients, one patient (2.4%) had grade B bile leakage. During the median follow-up of 12.6 months, one patient (2.4%) with bile leakage developed anastomotic stenosis. Perioperative mortality was not observed. A surgical video showing the posterior double-layer interrupted sutures in the robotic HJ is included. CONCLUSIONS: Posterior double-layer interrupted sutures in robotic HJ provided a simple and feasible method for biliary reconstruction with a low risk of biliary complications.

Locally Advanced Rectal Cancer Invading the Gluteus Maximus Muscle Completely Responded to Total Neoadjuvant Therapy.

A 70-year-old male with anal pain and fever was diagnosed with rectal cancer perforation and abscess in the right gluteus maximus (GM) muscle. He underwent a transverse colon colostomy followed by preoperative capecitabine+oxaliplatin. Some local control was achieved but a residual abscess was observed in the right GM muscle. To secure circumferential resection margin by tumor reduction, he received chemoradiotherapy as total neoadjuvant therapy (TNT) and underwent laparoscopic abdominoperineal resection, D3 lymph node dissection, combined coccyx resection, and partial resection of the right GM muscle. The skin defect and pelvic dead space were filled with a right lateral vastus lateral great muscle flap. Histopathologically, the resected specimen showed no tumor cells in the primary tumor or lymph nodes, indicating a pathological complete response (pCR). This case suggests that TNT might improve the R0 resection and pCR rates and overall survival.