Tumor-infiltrating monocytic myeloid-derived suppressor cells contribute to the development of an immunosuppressive tumor microenvironment in gastric cancer.

BACKGROUND: Gastric cancer (GC) is characterized by an immunosuppressive and treatment-resistant tumor immune microenvironment (TIME). Here, we investigated the roles of different immunosuppressive cell types in the development of the GC TIME. METHODS: Single-cell RNA sequencing (scRNA-seq) and multiplex immunostaining of samples from untreated or immune checkpoint inhibitor (ICI)-resistant GC patients were used to examine the correlation between certain immunosuppressive cells and the prognosis of GC patients. RESULTS: The results of the scRNA-seq analysis revealed that tumor-infiltrating monocytic myeloid-derived suppressor cells (TI-M-MDSCs) expressed higher levels of genes with immunosuppressive functions than other immunosuppressive cell types. Additionally, M-MDSCs in GC tissues expressed significantly higher levels of these markers than adjacent normal tissues. The M-MDSCs were most enriched in GC tissues relative to adjacent normal tissues. Among the immunosuppressive cell types assessed, the M-MDSCs were most enriched in GC tissues relative to adjacent normal tissues; moreover, their presence was most strongly associated with a poor prognosis. Immediate early response 3 (IER3), which we identified as a differentially expressed gene between M-MDSCs of GC and adjacent normal tissues, was an independent poor prognostic factor in GC patients (P = 0.0003). IER3+ M-MDSCs expressed higher levels of genes with immunosuppressive functions than IER3- M-MDSCs and were abundant in treatment-resistant GC patients. CONCLUSIONS: The present study suggests that TI-M-MDSCs, especially IER3+ ones, may play a predominant role in the development of the immunosuppressive and ICI-resistant GC TIME.

Higher incidence of cholelithiasis with Roux-en-Y reconstruction compared with Billroth-I after laparoscopic distal gastrectomy for gastric cancer: a retrospective cohort study.

PURPOSE: Cholelithiasis occurs often after gastrectomy. However, no consensus has been established regarding the difference in the incidence of postgastrectomy cholelithiasis with different reconstruction methods. In this study, we examined the frequency of cholelithiasis after two major reconstruction methods, namely Billroth-I (B-I) and Roux-en-Y (R-Y) following laparoscopic distal gastrectomy (LDG) for gastric cancer. METHODS: Among 696 gastric cancer patients who underwent LDG between April 2000 and March 2017, after applying the exclusion criteria, 284 patients who underwent B-I and 310 who underwent R-Y were examined retrospectively. The estimated incidence of cholelithiasis was compared between the methods, and factors associated with the development of cholelithiasis in the gallbladder and/or common bile duct were investigated. RESULTS: During the median follow-up of 61.2 months, 52 patients (8.8%) developed cholelithiasis postgastrectomy; 12 patients (4.2%) after B-I and 40 (12.9%) after R-Y (p = 0.0002). Among them, choledocholithiasis was more frequent in patients who underwent R-Y (n = 11, 27.5%) vs. B-I (n = 1, 8.3%) (p = 0.0056). Univariate and multivariate analyses revealed that male sex, body mass index > 22.5 kg/m2, and R-Y reconstruction were significant predictors of the development of postLDG cholelithiasis. CONCLUSION: Regarding cholelithiasis development, B-I reconstruction should be preferred whenever possible during distal gastrectomy.

Osteosarcopenia: the coexistence of sarcopenia and osteopenia is predictive of prognosis and postoperative complications after curative resection for colorectal cancer.

PURPOSE: To establish if osteosarcopenia is related to postoperative complications, prognosis, and recurrence of colorectal cancer (CRC) after curative surgery. METHODS: The clinical data of 594 patients who underwent curative resection for CRC between January, 2013 and December, 2018 were analyzed retrospectively to examine the relationship between clinicopathological data and osteosarcopenia. The following definitions were used: sarcopenia, low skeletal muscle mass index; osteopenia, low bone mineral density on computed tomography at the level of the 11th thoracic vertebra; and osteosarcopenia, sarcopenia with osteopenia. RESULTS: Osteosarcopenia was identified in 98 patients (16.5%) and found to be a significant risk factor for postoperative complications (odds ratio 2.53; p = 0.011). The 5-year overall survival (OS) and recurrence-free survival (RFS) rates of the patients with osteosarcopenia were significantly lower than those of the patients without osteosarcopenia (OS: 72.5% and 93.9%, respectively, p < 0.0001; RFS: 70.8% and 92.4%, respectively, p < 0.0001). Multivariate analysis identified osteosarcopenia as an independent prognostic factor associated with OS (hazard ratio 3.31; p < 0.0001) and RFS (hazard ratio 3.67; p < 0.0001). CONCLUSION: Osteosarcopenia may serve as a predictor of postoperative complications and prognosis after curative surgery for CRC.

Simple pelvimetry predicts the pelvic manipulation time in robot-assisted low and ultra-low anterior resection for rectal cancer.

PURPOSE: This study explored the difficulty factors in robot-assisted low and ultra-low anterior resection, focusing on simple measurements of the pelvic anatomy. METHODS: This was a retrospective analysis of the clinical data of 61 patients who underwent robot-assisted low and ultra-low anterior resection for rectal cancer between October 2018 and April 2023. The relationship between the operative time in the pelvic phase and clinicopathological data, especially pelvic anatomical parameters measured on X-ray and computed tomography (CT), was evaluated. The operative time in the pelvic phase was defined as the time between mobilization from the sacral promontory and rectal resection. RESULTS: Robot-assisted low and ultra-low anterior resections were performed in 32 and 29 patients, respectively. The median operative time in the pelvic phase was 126 (range, 31-332) min. A multiple linear regression analysis showed that a short distance from the anal verge to the lower edge of the cancer, a narrow area comprising the iliopectineal line, short anteroposterior and transverse pelvic diameters, and a small angle of the pelvic mesorectum were associated with a prolonged operative time in the pelvic phase. CONCLUSION: Simple pelvic anatomical measurements using abdominal radiography and CT may predict the pelvic manipulation time in robot-assisted surgery for rectal cancer.

Variations in the cystic duct: frequency and the relationship among insertion sides and heights on the bile duct.

BACKGROUND: Evaluation of the cystic duct anatomy prior to bile duct or gallbladder surgery is important, to decrease the risk of bile duct injury. This study aimed to clarify the frequency of cystic duct variations and the relationship between them. METHODS: Data of 205 patients who underwent cholecystectomy after imaging at Sada Hospital, Japan, were analyzed. The Chi-square test was used to analyze the relationships among variations. RESULTS: The lateral and posterior sides of the bile duct were the two most common insertion points (92 patients, 44.9%), and the middle height was the most common insertion height (135 patients, 65.9%). Clinically important variations (spiral courses, parallel courses, low insertions, and right hepatic duct draining) relating to the risk of bile duct injury were observed in 24 patients (11.7%). Regarding the relationship between the insertion sides and heights, we noticed that the posterior insertion frequently existed in low insertions (75.0%, P < 0.001) and did not exist in high insertions. In contrast, the anterior insertion coexisted with high and never low insertions. Spiral courses have two courses: anterior and posterior, and anterior ones were only found in high insertion cases. CONCLUSIONS: The insertion point of the cystic duct and the spiral courses tended to be anterior or lateral superiorly and posterior inferiorly. Clinically significant variations in cystic duct insertions are common and surgeons should be cautious about these variations to avoid complications.

Tertiary lymphoid structures correlate with enhancement of antitumor immunity in esophageal squamous cell carcinoma.

BACKGROUND: Tertiary lymphoid structures (TLSs) are associated with a favorable prognosis in several cancers. However, the correlation between TLSs and outcomes of esophageal squamous cell carcinoma (ESCC) and the impact of TLSs on the tumor immune microenvironment (TIME) remain unknown. METHODS: We pathologically evaluated the significance of TLSs in ESCC focusing on TLS maturation using 180 ESCC specimens and performed single-cell RNA sequencing (scRNA-seq) using 14 ESCC tissues to investigate functional differences of immune cells according to TLS presence. RESULTS: TLS+ cases had better recurrence-free-survival (RFS) (p < 0.0001) and overall survival (OS) (p = 0.0016) compared with TLS- cases. Additionally, mature TLS+ cases had better RFS and OS compared with immature TLS+ cases (p = 0.019 and p = 0.015) and TLS- cases (p < 0.0001 and p = 0.0002). The scRNA-seq showed that CD8+ T cells in TLS+ tumors expressed high levels of cytotoxic signatures and antigen-presentation of dendritic cells (DCs) was enhanced in TLS+ tumors. Immunohistochemistry showed that the densities of tumor-infiltrating CD8+ T cells and DCs were significantly higher in TLS+ tumors than those in TLS- tumors. CONCLUSIONS: These data suggest the prognostic and functional significance of TLSs in ESCC and provides new insights into TLSs on the TIME.

Clinicopathologic Features and Genetic Alterations in Mixed-Type Ampullary Carcinoma.

Mixed-type ampullary carcinoma is a subtype that combines intestinal-type (I-type) and pancreatobiliary-type (PB-type) lesions, but few studies have examined its clinicopathologic features and genetic alterations. The differences in genetic alterations between mixed type and other subtypes, as well as the genetic differences between I-type and PB-type lesions in the mixed type, remain unclear. In this study, we compared the clinicopathologic features and prognosis of 110 ampullary carcinomas classified by hematoxylin and eosin and immunohistochemical staining as follows: 63 PB-type, 35 I-type, and 12 mixed-type carcinomas. A comparative analysis of genetic mutations by targeted sequencing of 24 genes was also performed in 3 I-type cases, 9 PB-type cases, and I and PB-type lesions of 6 mixed-type cases. The mixed subtype had a poorer prognosis than the other subtypes, and there was also a similar tendency in the adjuvant group (n = 22). A total of 49 genetic mutations were detected in all 18 lesions for which genetic alteration was analyzed. No genetic mutations specific to the mixed type were found, and it was not possible to determine genetically whether the mixed type had originally been I or PB type. However, 5 of 6 cases had mutations common to both I and PB-type lesions, and additional mutations were found only in either I or PB-type lesions. In support of this, the mixed type more frequently exhibited genetic heterogeneity intratumorally than the other subtypes. Mixed-type tumors are histologically, immunohistochemically, and genetically heterogeneous, and this heterogeneity is associated with poor prognosis and may affect treatment resistance.

ERAP2 is a novel target involved in autophagy and activation of pancreatic stellate cells via UPR signaling pathway.

BACKGROUND/OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) is characterized by excessive desmoplasia and autophagy-dependent tumorigenic growth. Pancreatic stellate cells (PSCs) as a predominant stromal cell type play a critical role in PDAC biology. We have previously reported that autophagy facilitates PSC activation, however, the mechanism remains unknown. We investigated the mechanism of autophagy in PSC activation. METHODS: We compared gene expression profiles between patient-derived PSCs from pancreatic cancer and chronic pancreatitis using a microarray. The stromal expression of target gene in specimen of PDAC patients (n = 63) was analyzed. The effect of target gene on autophagy and activation of PSCs was investigated by small interfering RNAs transfection, and the relationship between autophagy and ER stress was investigated. We analyzed the growth and fibrosis of xenografted tumor by orthotopic models. RESULTS: In analysis of gene expression microarray, endoplasmic reticulum aminopeptidase 2 (ERAP2) upregulated in cancer-associated PSCs was identified as the target gene. High stromal ERAP2 expression is associated with a poor prognosis of PDAC patients. Knockdown of ERAP2 inhibited unfolded protein response mediated autophagy, and led to inactivation of PSCs, thereby attenuating tumor-stromal interactions by inhibiting production of IL-6 and fibronectin. In vivo, the promoting effect of PSCs on xenografted tumor growth and fibrosis was inhibited by ERAP2 knockdown. CONCLUSIONS: Our findings demonstrate a novel mechanism of PSCs activation regulated by autophagy. ERAP2 as a promising therapeutic target may provide a novel strategy for the treatment of PDAC.

Potential therapeutic targets discovery by transcriptome analysis of an in vitro human gastric signet ring carcinoma model.

BACKGROUND: Loss of E-cadherin expression is frequently observed in signet ring carcinoma (SRCC). People with germline mutations in CDH1, which encodes E-cadherin, develop diffuse gastric cancer at a higher rate. Loss of E-cadherin expression is thus assumed to trigger oncogenic development. METHODS: To investigate novel therapeutic targets for gastric SRCC, we engineered an E-cadherin-deficient SRCC model in vitro using a human gastric organoid (hGO) with CDH1 knockout (KO). RESULTS: CDH1 KO hGO cells demonstrated distinctive morphological changes similar to SRCC and high cell motility. RNA-sequencing revealed up-regulation of matrix metalloproteinase (MMP) genes in CDH1 KO hGO cells compared to wild type. MMP inhibitors suppressed cell motility of CDH1 KO hGO cells and SRCC cell lines in vitro. Immunofluorescent analysis with 95 clinical gastric cancer tissues revealed that MMP-3 was specifically abundant in E-cadherin-aberrant SRCC. In addition, CXCR4 molecules translocated onto the cell membrane after CDH1 KO. Addition of CXCL12, a ligand of CXCR4, to the culture medium prolonged cell survival of CDH1 KO hGO cells and was abolished by the inhibitor, AMD3100. In clinical SRCC samples, CXCL12-secreting fibroblasts showed marked infiltration into the cancer area. CONCLUSIONS: E-cadherin deficient SRCCs might gain cell motility through upregulation of MMPs. CXCL12-positive cancer-associated fibroblasts could serve to maintain cancer-cell survival as a niche. MMPs and the CXCL12/CXCR4 axis represent promising candidates as novel therapeutic targets for E-cadherin-deficient SRCC.

New high-throughput screening detects compounds that suppress pancreatic stellate cell activation and attenuate pancreatic cancer growth.

BACKGROUND/OBJECTIVES: Pancreatic stellate cells (PSCs) are involved in abundant desmoplasia, which promotes cancer cell aggressiveness and resistance to anti-cancer drugs. Therefore, PSCs are suggested to be a promising therapeutic target by attenuating PSC activation to inhibit tumor-stromal interactions with pancreatic cancer cells. Here, we developed a screen to identify compounds that reduce the activity of PSCs and investigated the effect of candidates on pancreatic cancer. METHODS: Lipid droplet accumulation in PSCs was used to observe differences in PSC activity and a new high-throughput screening platform that quantified lipid droplets in PSCs was established. A library of 3398 Food and Drug Administration-approved drugs was screened by this platform. Validation assays were performed in vitro and in vivo. RESULTS: Thirty-two compounds were finally selected as candidate compounds by screening. These compounds decreased α-smooth muscle actin expression and inhibited autophagic flux in PSCs in vitro. Among the candidates, three drugs selected for validation assays inhibited the proliferation and migration of PSCs and invasion of cancer cells by disrupting tumor-stromal interactions. Production of extracellular matrix molecules was also decreased significantly by this treatment. In vivo testing in xenograft models showed that dopamine antagonist zuclopenthixol suppressed tumor growth; this suppression was significantly increased when combined with gemcitabine. CONCLUSIONS: A new screening platform that focused on the morphological features of PSCs was developed. Candidate drugs from this screening suppressed PSC activation and tumor growth. This screening system may be useful to discover new compounds that attenuate PSC activation.

High frequency of bone recurrence as an initial recurrence site after radical surgery in T1N3 gastric cancer: a propensity score matching analysis.

PURPOSE: T1 gastric cancer (GC) with seven or more metastatic lymph nodes is extremely rare, and very few clinical studies have been conducted to evaluate the clinicopathological features of their recurrence. METHODS: We retrospectively analyzed the outcomes of T1 GC and T2-4 GC patients who had multiple nodal metastases after radical surgery from 2006 to 2020. Propensity score matching was performed to compare the two groups of patients. RESULTS: After propensity score matching, 18 of 22 patients in the T1 group and 36 of 144 patients in the T2-4 group were selected. Recurrence occurred in six patients (33.3%) in the T1 group. In the T1 group, the most common site of initial recurrence was bone (15.0%). The prevalence of bone recurrence was significantly higher in the T1 group than in the T2-4 group (P = 0.02). The median interval time between radical surgery and bone recurrence was 24 months, and the median survival time after bone recurrence was 14 months. CONCLUSION: Bone recurrence was more frequently identified as an initial recurrence site in T1 GC cases with multiple metastases after radical surgery compared with that in T2-4 GC cases. Careful attention should be paid to postoperative bone recurrence in the long-term postoperative course of these patients.

Mutations in the pancreatic secretory enzymes CPA1 and CPB1 are associated with pancreatic cancer.

To evaluate whether germline variants in genes encoding pancreatic secretory enzymes contribute to pancreatic cancer susceptibility, we sequenced the coding regions of CPB1 and other genes encoding pancreatic secretory enzymes and known pancreatitis susceptibility genes (PRSS1, CPA1, CTRC, and SPINK1) in a hospital series of pancreatic cancer cases and controls. Variants in CPB1, CPA1 (encoding carboxypeptidase B1 and A1), and CTRC were evaluated in a second set of cases with familial pancreatic cancer and controls. More deleterious CPB1 variants, defined as having impaired protein secretion and induction of endoplasmic reticulum (ER) stress in transfected HEK 293T cells, were found in the hospital series of pancreatic cancer cases (5/986, 0.5%) than in controls (0/1,045, P = 0.027). Among familial pancreatic cancer cases, ER stress-inducing CPB1 variants were found in 4 of 593 (0.67%) vs. 0 of 967 additional controls (P = 0.020), with a combined prevalence in pancreatic cancer cases of 9/1,579 vs. 0/2,012 controls (P < 0.01). More ER stress-inducing CPA1 variants were also found in the combined set of hospital and familial cases with pancreatic cancer than in controls [7/1,546 vs. 1/2,012; P = 0.025; odds ratio, 9.36 (95% CI, 1.15-76.02)]. Overall, 16 (1%) of 1,579 pancreatic cancer cases had an ER stress-inducing CPA1 or CPB1 variant, compared with 1 of 2,068 controls (P < 0.00001). No other candidate genes had statistically significant differences in variant prevalence between cases and controls. Our study indicates ER stress-inducing variants in CPB1 and CPA1 are associated with pancreatic cancer susceptibility and implicate ER stress in pancreatic acinar cells in pancreatic cancer development.

FoundationOne® CDx gene profiling in Japanese pancreatic ductal adenocarcinoma patients: a single-institution experience.

PURPOSE: The aim of this study was to investigate the genetic mutation profiles of Japanese pancreatic ductal adenocarcinoma (PDAC) patients. METHODS: Next-generation sequencing was performed using FoundationOne® CDx on 17 PDAC patients who were treated by surgical resection at Kyushu University Hospital between February 2016 and January 2019. The tumor mutational burden and microsatellite instability status were also assessed. RESULTS: There were 16 patients (94%) with KRAS mutations, 13 (76%) with TP53 mutations, three (18%) with SMAD4 mutations, and one (6%) with a CDKN2A mutation. All patients had at least one pathogenic variant or a likely pathogenic variant. No patient had targeted therapies that matched with any clinical benefit according to FoundationOne® CDx. An unresectable PDAC patient with BRCA2-mutant disease was successfully treated by conversion surgery using platinum-based neoadjuvant chemotherapy. CONCLUSIONS: Currently, FoundationOne® CDx might be difficult to use on PDAC patients, although further investigations with larger study populations are called for.

Concomitant Intraductal Papillary Mucinous Neoplasm in Pancreatic Ductal Adenocarcinoma Is an Independent Predictive Factor for the Occurrence of New Cancer in the Remnant Pancreas.

OBJECTIVE: To determine the factors predicting the subsequent development of pancreatic ductal adenocarcinoma in remnant pancreas (PDAC-RP) after partial pancreatectomy for PDAC. SUMMARY BACKGROUND DATA: PDAC-RP after partial pancreatectomy for PDAC is currently not so rare because of improved prognosis of PDAC patients due to recent advances in surgical techniques and adjuvant therapy. However, the predictive factors related to PDAC-RP remain unknown. METHODS: We retrospectively reviewed the clinicopathological data of a consecutive series of 379 patients with PDAC treated by partial pancreatectomy between 1992 and 2015; 14 patients (3.69%) had PDAC-RP. Clinicopathological variables were compared between PDAC-RP and non-PDAC-RP. RESULTS: In univariate analysis, concomitant intraductal papillary mucinous neoplasm (IPMN) (P = 0.0005), cancer location (body/tail) (P = 0.0060), and lower T factor in UICC (P = 0.0039) were correlated with PDAC-RP development. Multivariate analysis revealed concomitant IPMN (P = 0.0135) to be an independent predictive factor for PDAC-RP. PDAC concomitant with IPMN had higher cumulative incidence of PDAC-RP (47.5%/10 yrs) than PDAC without IPMN (9.96%/10 yrs) (P = 0.0071). Moreover, the density of pancreatic intraepithelial neoplasia lesions in the background pancreas of cases of PDAC concomitant with IPMN (1.86/cm) was higher than that of cases of PDAC without IPMN (0.91/cm) (P = 0.0007). CONCLUSIONS: Concomitant IPMN in PDAC is an independent predictive factor for the development of new PDAC in remnant pancreas. Cancer susceptibility of remnant pancreas after resection for PDAC concomitant with IPMN is probably due to an increased density of pancreatic intraepithelial neoplasia lesions.

Prevalence of Germline Mutations Associated With Cancer Risk in Patients With Intraductal Papillary Mucinous Neoplasms.

BACKGROUND & AIMS: Many patients with pancreatic adenocarcinoma carry germline mutations associated with increased risk of cancer. It is not clear whether patients with intraductal papillary mucinous neoplasms (IPMNs), which are precursors to some pancreatic cancers, also carry these mutations. We assessed the prevalence of germline mutations associated with cancer risk in patients with histologically confirmed IPMN. METHODS: We obtained nontumor tissue samples from 315 patients with surgically resected IPMNs from 1997 through 2017, and we sequenced 94 genes with variants associated with cancer risk. Mutations associated with increased risk of cancer were identified and compared with individuals from the Exome Aggregation Consortium. RESULTS: We identified 23 patients with a germline mutation associated with cancer risk (7.3%; 95% confidence interval, 4.9-10.8). Nine patients had a germline mutation associated with pancreatic cancer susceptibility (2.9%; 95% confidence interval, 1.4-5.4). More patients with IPMNs carried germline mutations in ATM (P < .0001), PTCH1 (P < .0001), and SUFU (P < .0001) compared with controls. Patients with IPMNs and germline mutations associated with pancreatic cancer were more like to have concurrent invasive pancreatic carcinoma compared with patients with IPMNs without these mutations (P < .0320). CONCLUSIONS: In sequence analyses of 315 patients with surgically resected IPMNs, we found that almost 3% to carry mutations associated with pancreatic cancer risk. More patients with IPMNs and germline mutations associated with pancreatic cancer had concurrent invasive pancreatic carcinoma compared with patients with IPMNs without these mutations. Genetic analysis of patients with IPMNs might identify those at greatest risk for cancer.

Influence of endoscopic resection on additional laparoscopic distal gastrectomy: a propensity score-matching analysis.

PURPOSE: There is no definite evidence of the feasibility and safety of laparoscopic distal gastrectomy (LDG) for patients who have undergone incomplete endoscopic resection (ER). We investigated the influence of ER prior to LDG by a propensity score matching analysis. METHODS: We retrospectively analyzed the outcomes of gastric cancer patients who underwent LDG with or without prior ER from 2000 to 2014. Propensity score matching was performed to compare the two groups of patients. RESULTS: After matching, 47 patients in the ER group and 94 patients in the non-ER group were selected from a total of 365 patients. A residual tumor was observed in 10 of 47 patients (21.3%). The mean number of dissected lymph nodes in the non-ER group (39.4 ± 14.5) was higher than that in the ER group (31.7 ± 13.5) (P = 0.003). However, other perioperative data, such as the operation time and blood loss volume were similar. The complication rate of the ER group (17.0%) and the non-ER group (9.6%) did not differ to a statistically significant extent (P = 0.2). Among these patients, 6 died during the 5-year follow-up period, but no patients showed signs of recurrence. CONCLUSION: ER prior to surgical resection showed no significant influence on postoperative complications or mortality. LDG can be safely performed to achieve radical resection after incomplete ER.

Subcutaneous fat area as a risk factor for extraction site incisional hernia following gastrectomy for gastric cancer.

PURPOSE: To identify the incidence of extraction site incisional hernia following gastrectomy for gastric cancer and its significant risk factors, including the subcutaneous fat area. METHODS: We reviewed data gathered prospectively on patients with gastric cancer, who underwent gastrectomy between 2008 and 2012 at Kyushu University Hospital, Fukuoka, Japan. The subcutaneous fat area (SFA) and visceral fat area (VFA) were measured using axial computed tomography at the level of the L4 and L3 transverse processes, and the L2-L3 intervertebral disc. The primary endpoint of the rate of extraction site incisional hernia was based on the computed tomography and clinical data including hospital follow-up reports. RESULTS: After applying the inclusion and exclusion criteria, 320 patients were included in this retrospective analysis: 3.1% (10/320) had extraction site incisional hernias after a mean follow-up of 11 months. Multivariate analysis revealed that age and the SFA were independent risk factors (age ≥ 70.5 years: P = .013, odds ratio: 9.116, 95% confidence interval 1.581-52.553; L4 SFA ≥ 124 cm2: P = .004, odds ratio: 13.752, 95% confidence interval 2.290-82.582). CONCLUSION: Age and the SFA were independent risk factors for extraction site incisional hernia in patients undergoing gastrectomy for gastric cancer.

Genome-Wide Somatic Copy Number Alterations and Mutations in High-Grade Pancreatic Intraepithelial Neoplasia.

To obtain a better understanding of the genetic alterations of high-grade pancreatic intraepithelial neoplasia (HG-PanIN), we performed whole-genome copy number analysis by using single nucleotide polymorphism microarrays and targeted next-generation sequencing of 11 microdissected HG-PanIN and two low-grade PanIN lesions associated with HG-PanIN. HG-PanIN mutation profiles were compared with those of their associated invasive pancreatic ductal adenocarcinoma. All PanIN lesions harbored somatic KRAS mutations. The most common copy number losses in the HG-PanIN were at the CDKN2A (9p21), TP53 (17p13), and SMAD4 (18q21) loci. Chromosomal losses in HG-PanIN were also found at 6p25-p24, 6q11-q27, 12q24, and 17q23-q24. Biallelic inactivation of CDKN2A and TP53 was detected in five of eight and in three of eight evaluable PanIN lesions, respectively. None of the HG-PanIN lesions had SMAD4 mutations or homozygous deletion. Copy number gains were noted at the MYC (8q24) and CCNE1 (19q12) loci and at 1q25-q31. Four HG-PanINs and one low-grade PanIN harbored chromothripsis-like regions. Five of seven pancreatic ductal adenocarcinomas evaluated had additional mutations that were not found in their associated HG-PanIN. HG-PanIN harbors widespread copy number alterations and commonly shows evidence of biallelic inactivation of CDKN2A and TP53 but not SMAD4. Chromothripsis events contribute to the copy number alterations of HG-PanIN.

Clinical assessment of the GNAS mutation status in patients with intraductal papillary mucinous neoplasm of the pancreas.

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is characterized by cystic dilation of the pancreatic duct, caused by mucin hypersecretion, with slow progression via the adenoma-carcinoma sequence mechanism. Mutation of GNAS at codon 201 is found exclusively in IPMNs, occurring at a rate of 41-75%. Recent advances in molecular biological techniques have demonstrated that GNAS mutation might play a role in the transformation of IPMNs after the appearance of neoplastic cells, rather than in the tumorigenesis of IPMNs. GNAS mutation is observed frequently in the intestinal subtype of IPMNs with MUC2 expression, and less frequently in IPMNs with concomitant pancreatic ductal adenocarcinoma (PDAC). Research has focused on assessing GNAS mutation status in clinical practice using various samples. In this review, we discuss the clinical application of GNAS mutation assessment to differentiate invasive IPMNs from concomitant PDAC, examine the clonality of recurrent IPMNs in the remnant pancreas using resected specimens, and differentiate pancreatic cystic lesions using cystic fluid collected by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA), duodenal fluid, and serum liquid biopsy samples.

Genetic analyses of isolated high-grade pancreatic intraepithelial neoplasia (HG-PanIN) reveal paucity of alterations in TP53 and SMAD4.

High-grade pancreatic intraepithelial neoplasia (HG-PanIN) is the major precursor of pancreatic ductal adenocarcinoma (PDAC) and is an ideal target for early detection. To characterize pure HG-PanIN, we analysed 23 isolated HG-PanIN lesions occurring in the absence of PDAC. Whole-exome sequencing of five of these HG-PanIN lesions revealed a median of 33 somatic mutations per lesion, with a total of 318 mutated genes. Targeted next-generation sequencing of 17 HG-PanIN lesions identified KRAS mutations in 94% of the lesions. CDKN2A alterations occurred in six HG-PanIN lesions, and RNF43 alterations in five. Mutations in TP53, GNAS, ARID1A, PIK3CA, and TGFBR2 were limited to one or two HG-PanINs. No non-synonymous mutations in SMAD4 were detected. Immunohistochemistry for p53 and SMAD4 proteins in 18 HG-PanINs confirmed the paucity of alterations in these genes, with aberrant p53 labelling noted only in three lesions, two of which were found to be wild type in sequencing analyses. Sixteen adjacent LG-PanIN lesions from ten patients were also sequenced using targeted sequencing. LG-PanIN harboured KRAS mutations in 94% of the lesions; mutations in CDKN2A, TP53, and SMAD4 were not identified. These results suggest that inactivation of TP53 and SMAD4 are late genetic alterations, predominantly occurring in invasive PDAC. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.