Minimally invasive D2 lymphadenectomy for gastric cancer is technically demanding, and its quality varies across patients, surgeons, platforms, and institutions. Conventional endpoints, including lymph node yield, margin status, operative time, blood loss, postoperative morbidity, and survival, remain essential but do not consistently capture intraoperative procedural fidelity, safety-critical deviations, or case complexity. This narrative framework review synthesized evidence from MEDLINE, Embase, and Web of Science from inception to May 10, 2026, focusing on technical difficulty, surgical quality assessment, pathology-centered oncologic adequacy, risk-adjusted outcomes, and artificial intelligence (AI)-enabled audit. Technical difficulty was conceptualized as a case- and context-dependent risk-adjustment layer shaped by anatomical complexity, vascular variation, therapy-altered tissue planes, visceral adiposity, operative platform, team workflow, and learning stage. Surgical quality was defined as a multidomain construct integrating process metrics, pathology metrics, and risk-adjusted clinical outcomes. The proposed framework provides audit-oriented guidance for identifying a simplified minimum dataset, prioritizing high-risk D2 segments for selective process review, and interpreting process, pathology, and outcome indicators together after adjustment for technical difficulty. AI may support scalable audit through video indexing, phase and step recognition, extraction of high-risk operative segments, assisted event logging, and structured feedback. However, AI outputs should be treated as candidate measurement signals requiring human confirmation, expert surgical review, pathology-based assessment, external validation, governance, and post-deployment monitoring. Future validation should proceed stepwise, from feasibility testing and inter-rater reliability assessment to prospective workflow evaluation and multicenter assessment of audit efficiency, benchmarking validity, and process- or patient-level outcomes. Quality assessment in minimally invasive D2 lymphadenectomy should shift from isolated surrogate endpoints toward an auditable, difficulty-adjusted framework that makes “D2 achieved” more measurable, reviewable, and clinically meaningful.

Preoperative assessment of lymph node dissection (LND) difficulty in gastric cancer remains challenging. Conventional clinical indicators are relatively coarse and may not adequately reflect tissue-related complexity within the surgical field. This study aimed to develop and validate a preoperative CT-based radiomics approach using suprapancreatic adipose tissue for predicting high-difficulty LND in gastric cancer. This single-center retrospective study included 192 patients with gastric cancer who underwent laparoscopic radical D2 gastrectomy between January 2022 and December 2024. Patients were randomly assigned to a training cohort (n = 134) and a validation cohort (n = 58). High-difficulty LND was defined as suprapancreatic LND time exceeding the 75th percentile (32.68 min) and/or unqualified suprapancreatic dissection according to KLASS-02-QC. A single-slice ROI was manually delineated in the suprapancreatic adipose tissue on portal venous-phase CT images. Radiomics features were extracted, followed by feature selection and model development. Four radiomics models, a clinical model, and a combined model were constructed. Sensitivity analyses were further performed using alternative time thresholds and in the subgroup without neoadjuvant chemotherapy (NCT). A total of 81 of 192 patients (42.2

Patients with functional esophageal disorders exhibit symptoms such as chest pain, heartburn, dysphagia, globus sensation, or reflux hypersensitivity in the absence of structural abnormalities. This is characterized by dysregulated gut-brain interactions and visceral hypersensitivity. A systematic search of the MEDLINE, EMBASE, Web of Science and the Cochrane central register of controlled trials databases was performed to December 31, 2025. Relevant randomized controlled trials (RCT) reporting the effects of gut–brain neuromodulator (GBN) therapy on functional chest pain (FCP), functional heartburn (FH), reflux hypersensitivity (RH), functional dysphagia (FD), and globus were analyzed. Among 2538 screened records, 29 RCTs were included. Neuromodulators provided symptom relief in 18–67

Proximal gastrectomy (PG) for proximal gastric cancer (PGC) is associated with complications such as gastroesophageal reflux. The double-flap technique (DFT) has been proposed as an effective anti-reflux reconstruction method. This systematic review aims to compare the safety and short-term outcomes of DFT versus other reconstruction methods for proximal gastrectomy. The present meta-analysis was conducted, following PRISMA guidelines. Studies comparing DFT with other reconstruction methods for proximal gastric cancer were included. Outcomes assessed included surgical parameters (operative time and intraoperative blood loss), postoperative reflux incidence (subjective reflux symptoms, objective evaluation using endoscopy and proton pump inhibitor (PPI) intake), and other short-term postoperative indicators (postoperative complications and length of postoperative hospital stay). Data were extracted from PubMed, Web of Science, EMBASE, and the Cochrane Library through June 1st, 2025. Risk of bias was assessed using the Newcastle-Ottawa Scale. We performed meta-analyses using Review Manager 5.4, presenting mean differences (MD) and odds ratios (OR) with 95

For early-stage proximal gastric cancer, proximal gastrectomy (PG) preserves gastric function but often causes severe gastroesophageal reflux that impairs quality of life. Because reconstruction geometry reshapes intragastric flow near the esophagogastric junction (EGJ), we aim to identify the key geometric-biomechanical factors in esophagogastric anastomosis that affect reflux. We conducted a clinical-computational fluid dynamics (CFD)-clinical closed-loop study to evaluate postoperative anti-reflux performance after PG. A retrospective analysis of 59 patients who received PG compared anti-reflux outcomes across standard reconstructions, enabling the identification of five procedural differences for CFD modeling. Using four patient-specific CFD models, single-variable analyses of five geometric features were conducted following virtual PG to quantify intragastric flow changes across geometries, with results compared to clinical data. The double-flap technique demonstrated an 84.2% reflux control rate, superior to other reconstructions (P = 0.001) and consistent with CFD-identified low-reflux geometry. CFD simulations confirmed that a lesser curvature site anastomosis, small anastomosis diameter, and cranial anastomosis angulation each independently reduced reflux (P < 0.05). Crucially, this study established a novel three-dimensional transient quantitative analysis for reflux, enabling direct comparison of reflux volume across geometries. Beyond total reflux, the EGJ vortex volume fraction and pressure recovery characteristics provided reliable flow-field metrics to distinguish reflux risk. Validation with non-Newtonian puree showed consistent performance of the low-reflux geometry across fluid types. Thus, we translate the success of the empirically optimal technique into a quantifiable and interpretable geometric-fluid dynamic standard, offering a validated and robust configuration for anti-reflux reconstruction after PG.

This study employs patient-specific computational fluid dynamics coupled with a Lagrangian discrete-phase model to quantify the influence of His angle and anastomotic caliber on intragastric hemodynamics after stomach-partitioning gastrojejunostomy (SPGJ). Three His angles (3°, 7°, 11°) and three stoma widths (narrow, intermediate, wide) were systematically analyzed. Within the physiological range, His angle altered global velocity and pressure by <5%, yet extreme values prolonged mean particle residence up to 1.9-fold, indicating a moderate angle (∼7°) minimizes stasis without elevating pressure loss. Stoma size proved decisive: very narrow or very wide orifices produced low-velocity seepage, high stagnation, and either excessive or moderate pressure drops, whereas an intermediate aperture yielded the lowest Δp and the shortest residence time. The results suggest that optimizing SPGJ requires maintaining a moderate His angle and designing an intermediate-sized anastomosis to maximize emptying efficiency while limiting tumor irritation and reflux risk. Clinically, these findings provide actionable guidance for intraoperative configuration and stoma sizing to balance functional patency with complication avoidance.

Stomach-partitioning gastrojejunostomy (SPGJ) improves gastric-outlet obstruction outcomes, yet its biomechanical basis and geometric optimization remain unclear. Patient computed tomography (CT) data were used to reconstruct realistic SPGJ models. Computational fluid dynamics combined with a discrete phase model quantified velocity, wall pressure, particle-retention time, and velocity under systematic variations of partitioning position (distal, mid, and proximal), partitioning angle (5°, 15°, and 25°; left- or right-sided), and incision angle (60°, 75°, and 90°). Distal partitioning produced the lowest pressure drop and fastest emptying, whereas proximal partitioning channeled high-speed flow toward the pylorus and prolonged retention. A ∼15° partitioning angle balanced flow restriction and clearance; extreme unilateral angles either increased particle stasis (left-side) or slowed emptying despite reduced reflux (right-side). A vertical incision (90°) further decreased pressure losses and shortened mean retention relative to oblique cuts. SPGJ biomechanics are highly geometry-sensitive. Distal placement, a 15° partitioning angle, and a near-vertical incision collectively optimize flow, reduce lesion contact, and accelerate gastric emptying, providing quantitative guidance for patient-specific SPGJ design.

The Sentinel Lymph Node (SLN) is the primary lymph node that receives lymphatic drainage from a tumor. Sentinel lymph node biopsy (SLNB) has become an indispensable tool for surgical guidance and therapeutic decision in surgical oncology. SLNB enables targeted surgical interventions while preserving patients' postoperative quality of life and refining prognostic evaluations. This review delves into the role and current status of SLN in gastric, colorectal, breast, thyroid, pancreatic, hepatic, gallbladder diseases and other sites. Variations in anatomy and techniques specific to each organ are explained, and the current role of SLNB in diagnosis and treatment is discussed. Enhancements of technologies in imaging and pathological examination, along with supplementary tools is also included. Future research should prioritize clinical evidence to support SLN's practical use while ensuring efficacy and safety.

PURPOSE:This study aimed to develop an artificial intelligence (AI) model for the surgical report output of laparoscopic lymph node dissection in the suprapancreatic region during gastric cancer surgery. METHODS:Patients who underwent laparoscopic radical resection for gastric cancer were included in this study, and their surgical videos were analyzed. The videos were recorded from the opening of the gastropancreatic fold as the starting point to the transection of the left gastric artery as the endpoint, with the video frame rate set to 1 frame per second. All surgical procedures were recorded following the principle of tool-tissue interaction, with annotations completed by an experienced surgeon and reviewed by a senior surgeon. The final annotated surgical videos were used as inputs for the AI model to generate the surgical report output. RESULTS:A total of 100 patients who underwent laparoscopic surgery for gastric cancer were included. A Surgical Concept Alignment Network was used as the model for surgical report output. The average number of frames in the videos was 728.71, with the grasping forceps being the most frequently used instrument. The AI model successfully generated a surgical video report output, achieving a BLEU-4 score of 0.7377, METEOR score of 0.4846, and ROUGE-L score of 0.7953. CONCLUSION:The AI model demonstrates its capability in producing surgical report output for laparoscopic lymph node dissection in the suprapancreatic region during gastric cancer surgery. This model serves as a valuable tool in clinical diagnosis, treatment, and training.

Gastric cancer is a common and highly invasive type of malignant tumor, the pathogenesis of which remains unclarified. However, exosomes are now known to play important roles in gastric cancer development and treatment. Cells use exosomes for the packaging and transportation of a variety of bioactive molecules, such as proteins, double-stranded DNA, and micro-ribonucleic acids, to other sites. Exosome-specific membrane structures and exosomal contents are widely involved in processes that facilitate material exchange and intercellular communication between gastric cancer cells. They help in forming a pre-metastatic microenvironment, promoting the proliferation and apoptosis of gastric cancer cells, and driving invasion, metastasis, and resistance to anti-tumor drugs. In this review, we aimed to summarize the findings of research articles indexed in the PubMed, Web of Science, and Embase databases and published up to May 31, 2024, on the role of exosomes in the pathogenesis of gastric cancer and their potential clinical applications in its treatment. Thus, research on exosomes may lead to breakthroughs in the early diagnosis of gastric cancer and identification of novel treatments.

Adenocarcinoma of the esophagogastric junction (AEG) has a high incidence, while the extent of lymph node dissection and prognosis are still controversial. This study aimed to explore the risk factors of lymph node metastasis and prognosis in Siewert II/III AEG patients. Between July 2013 and May 2017, a total of 65 patients who underwent surgical operation in Beijing Friendship Hospital were retrospectively reviewed. The patients were followed up until September 2017. Data were analyzed using logistic regression. Survival analyses were performed using Kaplan-Meier. Multivariate analysis revealed that histologic classification (OR=3.437, 95% CI: 1.046~11.294, P=0.042) and intravascular cancer embolus (OR=6.614, 95% CI: 1.942~22.524, P=0.003) were correlated with lymph node metastasis. The lymph nodes No. 1, 2, 3, 7, 11 and 110 indicated higher metastatic rate. The 3-year overall survival analysis revealed that lymph node metastasis (P=0.167) and tumor stage (P=0.429) exhibited no significant differences. Findings suggest that histologic type and vascular neoplasia are independent risk factors for lymph node metastasis. For Siewert II/III AEG patients, it is reasonable to perform radical gastrectomy combined with D2 lymph node dissection. For No. 110 lymph nodes should be dissected routinely. However, the long-term prognosis remains to be further studied.

IntroductionBenign gastric outlet obstruction (BGOO) severely impacts the quality of life of patients. The main treatment methods for BGOO include surgery and endoscopy, but both have significant drawbacks. Therefore, this study aims to explore the safety and efficacy of a new technique, to develop a new option for treating BGOO.Methods and analysisThis is an ongoing prospective, single-centre, single-blind randomised controlled trial. The study will be conducted from January 2022 to December 2025, and 50 patients will be enrolled. The participants will be randomly assigned in a 1:1 ratio to either the experimental (stomach-partitioning gastrojejunostomy with distal selective vagotomy) or control groups (conventional gastrojejunostomy with highly selective vagotomy). We will collect baseline characteristics, laboratory tests, auxiliary examinations, operation, postoperative conditions and follow-up data. Follow-up will last for 3 years. The main outcome is the incidence of delayed gastric emptying within 30 days after surgery. Secondary outcomes include the efficacy indicator (consisting of serum gastrin level, pepsinogen level, 13C breath test, gastrointestinal quality of life index, operation time, blood loss and postoperative recovery), a safety evaluation index (consisting of complications and mortality within 30 days after surgery) and follow-up data (consisting of the incidence of primary ulcer progression in 3 years after surgery, and the gastroscopy results in 1 and 3 years after surgery).Ethics and disseminationThis study was approved by the Ethics Committee of Beijing Friendship Hospital, Capital Medical University (no. 2021-P2-274-02). The study conformed to the provisions of the Declaration of Helsinki (as revised in 2013). Written informed consent will be obtained prior to study enrolment. The results of this study will be published in peer-reviewed publications.Trial registration numberChiCTR2100052197.

PurposeThe purpose of this meta-analysis is to systematically review the diagnostic performance of radiomic techniques in predicting peritoneal metastasis in patients with gastric cancer, and to evaluate the quality of current research.MethodsWe searched PubMed, Web of Science, EBSCO, Embase, and Cochrane databases for relevant studies up to April 3, 2023. Data extraction and quality evaluation were performed by two independent reviewers. Then we performed statistical analysis, including plotting the forest plot and summary receiver operating characteristic (SROC) curve, and source of heterogeneity analysis, through the MIDAS module in Stata 15. We performed meta-regression and subgroup analyses to analyze the sources of heterogeneity. Using the QUADAS-2 scale and the RQS scale to assess the quality of retrieved studies.ResultsTen studies with 6199 patients were finally included in our meta-analysis. Pooled sensitivity and specificity were 0.77 (95% confidence interval [CI]: 0.66, 0.86), and 0.88 (95% CI 0.80, 0.93), respectively. The overall AUC was 0.89 (95% CI 0.86, 0.92). The heterogeneity of this meta-analysis was high, with I-2 = 88% (95% CI 75,100). The result of meta-regression showed that QUADAS-2 results, RQS results and machine learning method led to heterogeneity in sensitivity and specificity (P < 0.05). Furthermore, the image segmentation area and the presence or absence of combined clinical factors were associated with sensitivity heterogeneity and specificity heterogeneity, respectively.ConclusionUndoubtedly, radiomics has potential value in diagnosing peritoneal metastasis of gastric cancer, but the quality of current research is inconsistent, and more standardized and high-quality research is still needed in the future to achieve the transformation of radiomics results into clinical applications.

Purpose This study aimed to evaluate the safety and efficacy of augmented-rectangle technique (ART) versus delta-shaped anastomosis (DA) for treating gastric cancer in total laparoscopic distal gastrectomy. Methods In total, 99 patients with distal gastric cancer who underwent ART ( n = 60) or DA ( n = 39) were considered. Operative data, postoperative recovery, complications, quality of life, and endoscopic findings of both groups were compared. Results The ART group had faster postoperative recovery than the DA group, and was better than DA regarding complications. The mode of reconstruction remained an independent predictor of complications, but not postoperative recovery. Dumping syndrome occurred in 3 (5.0%) and 2 patients (5.1%) of ART and DA groups within 30 days after surgery, and 3 (5.0%) and 2 patients (5.1%) 1 year after surgery. Regarding global health status on the EORTC-QLQ-C30 scale, the ART group had better outcomes than the DA group. Gastritis occurred in 38 (63.3%) and 27 (69.3%) patients of ART and DA groups, respectively. Residual food occurred in 8 (13.3%) and 11 (28.2%) patients of ART and DA groups. Reflux esophagitis occurred in 5 (8.3%) and 4 (10.3%) patients of ART and DA groups. Further, bile reflux occurred in 8 (13.3%) and 4 (10.3%) patients of ART and DA groups. Conclusions ART has similar advantages to DA for total laparoscopic reconstruction and is superior to DA regarding the incidence of complications, complication grade, and global health status. Furthermore, ART may have potential advantages in postoperative recovery and anastomotic stenosis.

Purpose: This study evaluated the gastric emptying performance of stomach-partitioning gastrojejunostomy (SPGJ) versus conventional gastrojejunostomy (CGJ) for treating gastric outlet obstruction (GOO). Methods: First, 73 patients who underwent SPGJ (n = 48) or CGJ (n = 25) were involved. Surgical outcomes, postoperative recovery of gastrointestinal function, delayed gastric emptying, and nutritional status of both groups were compared. Second, a three-dimensional stomach model was constructed based on the gastric filling CT images from a GOO patient with a standard stature. The present study evaluated SPGJ numerically by comparing it with CGJ in terms of local flow parameters such as flow velocity, pressure, particle retention time, and particle retention velocity. Results: Clinical data found that SPGJ had significant advantages over CGJ in terms of time to pass gas (3 versus 4 days, p < 0.001), time to oral intake (3 versus 4 days, p = 0.001), postoperative hospitalization (7 versus 9 days, p < 0.001), the incidence of delay gastric emptying (DGE) (2.1% versus 36%, p < 0.001), DGE grading (p < 0.001), and complications (p < 0.001) for GOO patients. Moreover, numerical simulation revealed that the SPGJ model would induce contents in stomach discharge to the anastomosis at a higher speed, and only 5% of that flowed to the pylorus. SPGJ model also had a low-pressure drop as the flow from the lower esophagus to the jejunum, reducing the resistance to food discharge. Besides, the average retention time of particles in the CGJ model is 1.5 times longer than that in the SPGJ models, and the average instantaneous velocity in CGJ and SPGJ models are 22 mm/s and 29 mm/s, respectively. Conclusion: Compared with CGJ, patients after SPGJ had better gastric emptying performance and better postoperative clinical efficacy. Therefore, we think that SPGJ may be a better option for treating GOO.

At present，radical total gastrectomy is still the main treatment method for esophagogastric junction adenocarcinoma（AEG）. However，due to the low rate of distal lymph node metastasis in early AEG，total gastrectomy without any choice may lead to unnecessary lymph node dissection in some patients，increase surgical trauma，and seriously affect the postoperative quality of life of patients. Therefore，how early AEG can minimize surgical trauma，preserve part of gastric function and improve patients’quality of life on the premise of ensuring the radical treatment of tumors has gradually become the focus of scholars. In recent years，more and more scholars at home and abroad recommend proximal gastrectomy，which has the advantages of better postoperative quality of life，and the disadvantages of higher gastroesophageal reflux and anastomotic stenosis rate. Therefore，in order to improve this deficiency，Many new anastomotic methods，including Side-overlap，double muscle flap anastomosis，jejunal interposition and double channel anastomosis，emerged. However，there is no consensus or guideline on how to choose the best proximal gastro-digestive reconstruction. Therefore，this article reviews the progress of digestive tract reconstruction after proximal gastrectomy，hoping to provide reference for the selection of the best anastomotic method.

Purpose Side overlap with fundoplication by Yamashita (SOFY) is an anti-reflux form of esophagogastrostomy. We compared the safety and efficacy of laparoscopic proximal gastrectomy (PG) with SOFY to that of laparoscopic total gastrectomy (TG) with Roux-en-Y for treating cT1-2 Siewert II/III adenocarcinoma of the esophagogastric junction. Methods Fifty-two patients who underwent PG (n = 28) or TG (n = 24), without conversion to laparotomy, were included. Surgical outcomes, complications, reflux symptoms, quality of life, and nutritional status of both groups were compared. Results Significant differences between PG and TG groups regarding operative time (245.7 versus 294.6 min, P = 0.005), reconstruction time (22.1 versus 28.5 min, P < 0.001), time to pass gas (3 versus 4 days, P = 0.021), time to oral intake (4.5 versus 5 days, P = 0.043), and gastroesophageal reflux (60.7% versus 4.2%, P < 0.001) were observed. Reflux esophagitis for the PG group was 42.9% (12/28). The incidence of Los Angeles grade B and above was 10.7%. Between-group differences in terms of global health status, diarrhea, reflux, and eating were observed. Body weight maintenance was better in the PG group than in the TG group 6 months and 1 year postoperatively. Conclusion SOFY is simple and more advantageous than TG in terms of postoperative recovery, body weight, eating, and diarrhea. However, the occurrence of postoperative reflux after SOFY was high. The limitations of this study are the significant differences in pathological T stage of patients in the two groups and the small sample size.

Gastrojejunostomy is a prominent approach in managing distal gastric cancer that is unresectable due to gastric outlet obstruction (GOO). Research has demonstrated that stomach-partitioning gastrojejunostomy (SPGJ) exhibits superior clinical efficacy compared to conventional gastrojejunostomy (CGJ), however, the underlying mechanism of this phenomenon remains elusive. This study constructed 3D models of the SPGJ and CGJ based on the computed tomography (CT) images obtained from a patient diagnosed with distal gastric cancer. The biomechanical patterns of these procedures in the digestive system were subsequently compared through numerical simulations and in vitro experiments. The results of the numerical simulation demonstrated that the model following SPGJ promoted the discharge of food through the anastomotic orifice and into the lower jejunum. Furthermore, a decrease in passage size after partitioning, the low-level velocity of esophageal, and an increase in contents viscosity effectively inhibited the flow through the passage to the pylorus, ultimately reducing stimulation to tumor. The study also revealed that favorable gastric emptying is associated with a smaller passage and faster inlet velocity, and that lower contents viscosity. ​The experimental findings conducted in vitro demonstrated that SPGJ exhibited superior efficacy in obstructing the flow near the pylorus in comparison to CGJ. Moreover, a decrease in passage size correlates with a reduction in fluid flow towards the pylorus. These results provide the foundation of theory and practice for the surgical management of patients with GOO resulting from unresectable distal gastric cancer, and have potential implications for clinical interventions.

Objective:To compare the clinicopathological and diagnositic features of Borrmann typeⅣ gastric cancer (GC) with other advanced GC and explore prognostic factors of the patients with Borrmann type Ⅳ GC.Methods:A retrospective cohort analysis was performed in 612 patients undergoing surgery for advanced GC who were admitted to Beijing Friendship Hospital Capital Medical University from January 2013 to January 2021. The clinical diagnosis and pathological features of 80 patients (13.1%) with Borrmann typeⅣ and 532 patients (86.9%) with other Borrmann types of GC were compared. Kaplan-Meier method was used to describe the survival curve, and Cox proportional hazard model was used to analyze the univariate and multivariate survival.Results:There were statistically significant differences in age, family history of gastrointestinal tumor, surgical method, R0 resection, maximum tumor diameter, tumor area, tumor site, histopathological type, degree of differentiation, depth of invasion, lymph node metastasis and TNM stage among GC patients with Borrmann type Ⅳ compared with other Borrmann types (all P<0.05). The diagnostic accuracy rates of enhanced CT scan and visual gastroscopy of Borrmann type Ⅳ GC were 80.0% and 81.2% respectively, lower than 91.4% and 91.8% of other Borrmann types (all P<0.05). The positive rates of first gastroscopic biopsy of Borrmann type Ⅳ GC were 72.5%, which was significantly lower than 93.7% of other Borrmann types (P<0.05). There was no significant difference in the diagnostic level of upper gastrointestinal tract angiography between the two groups (96.2% vs 91.9%, χ2=0.593, P=0.701). Univariate and multivariate analysis showed that surgical method, tumor distribution, vascular invasion and whether to regulate chemotherapy were independent prognostic factors for GC patients with Borrmann typeⅣ (all P<0.05).Conclusions:Borrmann type Ⅳ GC has unique clinicopathological characteristics, which requires multiple examination methods for identification. Surgical method, tumor distribution, vascular invasion and whether to regulate chemotherapy are important prognostic factors for Borrmann type Ⅳ GC.