Microenvironmental changes in familial adenomatous polyposis during colorectal cancer carcinogenesis

Familial adenomatous polyposis (FAP) is a heritable disease that increases the risk of colorectal cancer (CRC) development because of heterozygous mutations in APC. Little is known about the microenvironment of FAP. Here, single-cell RNA sequencing was performed on matched normal tissues, adenomas, and carcinomas from four patients with FAP. We analyzed the transcriptomes of 56,225 unsorted single cells, revealing the heterogeneity of each cell type, and compared gene expression among tissues. Then we compared the gene expression with that of sporadic CRC. Furthermore, we analyzed specimens of 26 FAP patients and 40 sporadic CRC patients by immunohistochemistry. Immunosuppressiveness of myeloid cells, fibroblasts, and regulatory T cells was upregulated even in the early stages of carcinogenesis. CD8+ T cells became exhausted only in carcinoma, although the cytotoxicity of CD8+ T cells was gradually increased according to the carcinogenic step. When compared with those in the sporadic CRC microenvironment, the composition and function of each cell type in the FAP-derived CRC microenvironment had differences. Our findings indicate that an immunosuppressive microenvironment is constructed from a precancerous stage in FAP.

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.

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.

Risk factors and clinical significance of subcutaneous emphysema after robot-assisted laparoscopic rectal surgery: a single-center experience

Subcutaneous emphysema (SE) is a complication of laparoscopic surgery, potentially resulting in severe respiratory failure. No reports to date have focused on SE during robot-assisted (RA) rectal surgery. We aimed to reveal the risk factors and clinical significance of SE after RA/laparoscopic rectal surgery. We retrospectively reviewed 221 consecutive patients who underwent RA/laparoscopic rectal surgery. The occurrence of SE was evaluated on postoperative radiographs. Laparoscopic surgery was performed in 120 patients and RA in 101. SE developed in 55 (24.9%) patients. Logistic regression analysis identified RA surgery (odds ratio [OR]: 4.89, 95% confidence interval [CI] 2.13-11.22, p < 0.001), higher age (OR: 1.06, 95% CI 1.03-1.11, p < 0.001), lower body mass index (BMI) (OR: 0.79, 95% CI 0.67-0.93, p = 0.004), thinner subcutaneous layer (OR: 0.88, 95% CI 0.79-0.98, p = 0.02), and lateral lymph node dissection (OR: 9.43, 95% CI 2.44-36.42, p < 0.001) as risk factors for SE. Maximum end-tidal CO2 was significantly higher in the SE than the non-SE cohort (p < 0.001). There was no difference in postoperative complication rate or length of hospital stay. Lower BMI (OR: 0.79, 95% CI 0.62-0.97, p = 0.02) and thinner subcutaneous layer (OR: 0.84, 95% CI 0.71-0.97, p = 0.01) were predictive factors in the RA cohort. SE occurs more frequently in RA compared with laparoscopic surgery. SE has a modest impact on short-term outcomes, but may occasionally cause severe problems. The indication of RA surgery should be considered carefully in high-risk elderly patients.

Combined endoscopic stenting and laparoscopic stent fixation for benign gastric tube stricture after esophagectomy: a case report

BACKGROUND

There are several options for the treatment of gastrointestinal stricture, including endoscopic stent placement and bypass surgery. However, a benign stricture is difficult to manage in a reconstructed gastric tube in the thoracic cavity owing to the technical difficulty of bypass surgery, and the possibility of stent migration.

CASE PRESENTATION

A 78-year-old woman was admitted to our hospital for treatment for her inability to eat. She had undergone video-assisted subtotal esophagectomy with retromediastinal gastric tube reconstruction 7 years earlier. At the current admission, there was a severely dilated gastric tube in the thoracic cavity with a soft stricture immediately anterior to the spine. Conservative therapy was ineffective; therefore, endoscopic stenting was performed. However, the stent migrated to the upper side of the stricture because the stricture was mild, and the stent was not fixed in the gastric tube. Next, endoscopic stent placement followed by laparoscopic stent fixation was performed. The stent was patent and worked well, and the patient's body weight increased. However, the stent collapsed 2 years later, with recurrence of symptoms. Stent-in-stent placement with an over-the-scope clip was performed, and the second stent was also patent and worked well.

CONCLUSIONS

Laparoscopic stent fixation with endoscopic stent placement could be an effective option for patients with a benign stricture in the reconstructed gastric tube.

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.

Endoscopic stent placement with laparoscopic stent fixation in a patient with obstruction at a gastrojejunostomy anastomosis site

BACKGROUND

Palliative endoscopic stent placement may be considered in patients with malignant gastrointestinal obstruction. Stent migration is a potential complication, particularly for those placed at a surgical anastomosis or across a stricture caused by extra-alimentary tract factors. We report a patient with left renal pelvis cancer and gastrojejunostomy obstruction who underwent endoscopic stent placement and laparoscopic stent fixation.

CASE PRESENTATION

A 60-year-old male with peritoneal dissemination of a left renal pelvis cancer was admitted for treatment of upper gastrointestinal obstruction. A laparoscopic gastrojejunostomy had been previously performed for cancer invasion of the duodenum. Imaging showed gastroduodenal dilation and impaired passage of contrast medium through the efferent loop of the gastrojejunostomy. Gastrojejunostomy anastomosis site obstruction due to dissemination of left renal pelvis cancer was diagnosed. Conservative treatment failed and endoscopic stent placement with laparoscopic stent fixation was performed. After surgery, the patient was able to tolerate oral intake and he was discharged without complications. The patient gained weight and was able to resume chemotherapy, indicating the procedure was effective.

CONCLUSIONS

Endoscopic stent placement with laparoscopic stent fixation for malignant upper gastrointestinal obstruction appears effective in patients with a high risk of stent migration.

Neoadjuvant chemotherapy enhances anti-tumor immune response of tumor microenvironment in human esophageal squamous cell carcinoma

Although chemotherapy has been an essential treatment for cancer, the development of immune checkpoint blockade therapy was revolutionary, and a comprehensive understanding of the immunological tumor microenvironment (TME) has become crucial. Here, we investigated the impact of neoadjuvant chemotherapy (NAC) on immune cells in the TME of human esophageal squamous cell carcinoma using single cell RNA-sequencing. Analysis of 30 fresh samples revealed that CD8+/CD4+ T cells, dendritic cells (DCs), and macrophages in the TME of human esophageal squamous cell carcinoma showed higher levels of an anti-tumor immune response in the NAC(+) group than in the NAC(-) group. Furthermore, the immune cells of the NAC(+) group interacted with each other resulting in enhanced anti-tumor immune response via various cytokines, including IFNG in CD8+/CD4+ T cells, EBI3 in DCs, and NAMPT in macrophages. Our results suggest that NAC potentially enhances the anti-tumor immune response of immune cells in the TME.

Single-cell transcriptome analysis reveals functional changes in tumour-infiltrating B lymphocytes after chemotherapy in oesophageal squamous cell carcinoma

BACKGROUND

Tumour immune microenvironment is related with carcinogenesis and efficacy of immunotherapy. B cells play major roles in humoral immunity, but detailed functions of tumour-infiltrating B lymphocytes (TIL-Bs) are unknown. Therefore, our aim was to investigate the functional heterogeneity of TIL-Bs in oesophageal squamous cell carcinoma (ESCC) and lymph nodes (LNs) during chemotherapy.

METHODS

Single-cell transcriptome analysis was performed on 23 specimens. We also performed immunohistochemical analysis of immunoglobulin κ C (IGKC), an antibody-secreting cell (ASC) marker, in 166 ESCC samples and evaluated the implication of IGKC in 2-year recurrence free survival (RFS) and 3-year overall survival (OS).

RESULTS

A total of 81,246 cells were grouped into 24 clusters. We extracted B cell clusters based on canonical markers and identified 12 TIL-B subtypes in ESCC. We found that several functions, such as co-stimulation and CD40 signalling, were enhanced in TIL-Bs after chemotherapy. The proportion of naive B cells (NBCs) decreased and B cell activation genes were up-regulated in NBCs after chemotherapy. The proportion of ASCs in tumours increased with the loss of migratory abilities and antibody production in ASCs was promoted after chemotherapy. Differentially expressed genes up-regulated with chemotherapy in ASCs correlated with prolonged survival with oesophageal cancer (p = .028). In a metastatic LN, the ASC proportion increased and B cell differentiation was enhanced. In immunohistochemical analysis, RFS and OS of high IGKC expression cases were significantly better than those of low IGKC expression cases (RFS: p < .0001, OS: p < .0001). And in multivariable analysis, the expression of IGKC was an independent favourable prognostic factor for RFS (hazard ratio (HR): 0.23, 95% confidence interval (CI): 0.12-0.45, p < .0001) and OS (HR: 0.20, 95% CI: 0.086-0.47, p = .0002) in ESCC.

CONCLUSIONS

Our findings provide novel insights for the heterogeneity of TIL-Bs during chemotherapy and will be useful to understand the clinical importance of TIL-Bs.

A novel germline mutation of TP53 with breast cancer diagnosed as Li-Fraumeni syndrome

TP53 is a tumor suppressor gene and, when dysfunctional, it is known to be involved in the development of cancers. Li-Fraumeni syndrome (LFS) is a hereditary tumor with autosomal dominant inheritance that develops in people with germline pathogenic variants of TP53. LFS frequently develops in parallel to tumors, including breast cancer. We describe a novel germline mutation in TP53 identified by performing a multi-gene panel assay in a breast cancer patient with bilateral breast cancer.

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.

Clinical impact of remnant lymphatic invasion on the recurrence of esophageal squamous cell carcinoma after esophagectomy with neoadjuvant chemotherapy

For stage II and III esophageal squamous cell carcinoma (ESCC), neoadjuvant chemotherapy (NAC) followed by esophagectomy is recommended in the Japanese guidelines for the diagnosis and treatment of esophageal cancer. However, recurrence of ESCC is common regardless of the NAC regimen and surgical method, and NAC demonstrates limited efficacy against recurrence. Therefore, the present study was conducted to identify risk factors of recurrence of ESCC with surgery after NAC. The outcomes of 51 patients who underwent esophagectomy for ESCC after NAC from 2010 to 2017 at Kyushu University Hospital were retrospectively analyzed. A total of 52 patients with ESCC without NAC followed by esophagectomy from 2001 to 2017 were selected for comparison. Among patients who underwent NAC followed by surgery, only lymphatic invasion (LY; hazard ratio, 2.761; 95% CI, 1.86-6.43, P=0.018) was an independent factor significantly associated with 3-year recurrence-free survival in the multivariate analysis. In patients with pathologic lymph node metastasis (pN) and no LY after NAC, there was significantly less recurrence compared with patients with pN and LY (P=0.0085), whereas in patients without LY after NAC, the presence of pN was not significantly associated with recurrence (P=0.2401). There were significantly fewer LY (+) patients in the NAC (+) group (P=0.0158) compared with those in the NAC (−) group. The presence of LY was an independent risk factor for recurrence of ESCC after esophagectomy following NAC. Overall, adjuvant treatment after surgery may be required in cases with remnant LY after NAC.

RNF43 as a predictor of malignant transformation of pancreatic mucinous cystic neoplasm

Mucinous cystic neoplasm (MCN) of the pancreas rarely progresses to invasive carcinoma, but few studies have analyzed genomic alterations involved in its malignant transformation. The relationships of ring finger protein 43 (RNF43) mutations with cytological atypia, RNF43 protein expression, and Wnt signaling proteins in MCN remain unclear. This study included 106 MCN cases, classified into 89 low-grade dysplasia (LG), 9 high-grade dysplasia (HG), and 8 invasive carcinoma (INV). We analyzed HG/INV and LG lesions of 9 HG/INV cases and LG lesions of 9 LG cases using targeted sequencing and confirmed the protein expression of RNF43 and β-catenin. The frequency of RNF43 mutations was significantly higher in HG/INV cases than in LG cases. Furthermore, HG/INV lesions (56%) and LG lesions (33%) of HG/INV cases possessed RNF43 mutation, whereas no such mutation was detected in any LG cases. The expression of RNF43 was reduced in 71% of HG/INV cases and significantly correlated with histological grade and aberrant expression of β-catenin. In 3 of 5 RNF43-mutated cases, the expression of RNF43 was reduced, but there was no significant correlation between RNF43 mutation and protein expression. MCNs frequently harbored KRAS mutations, at rates of 100% in HG/INV lesions and 50% in LG lesions of HG/INV and LG cases. There was no significant difference in mutation frequency in LG lesions between HG/INV and LG cases. These results suggest that RNF43 mutations may be involved in and predictive of malignant transformation from an early stage of MCN.

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.

Risk factors for postoperative pneumonia after laparoscopic gastrectomy in patients aged 75 years and over with gastric cancer

INTRODUCTION

The proportion of patients aged 75 years and over who undergo minimally invasive surgery for gastric cancer is increasing. However, the safety and feasibility of laparoscopic gastrectomy (LG) in this age group is controversial. This study aimed to evaluate whether LG is safe and effective in patients aged 75 years and over.

METHODS

The study included 728 patients with early and advanced gastric cancer who underwent curative LG between 2009 and 2017; 166 of these patients (22.8%) were aged 75 or over. All surgeries were performed laparoscopically. Selected clinical factors were compared between the 166 patients aged 75 years and over and the 562 patients aged under 75 years.

RESULTS

There were significant differences in presence of comorbidity, respiratory function and American Society of Anesthesiologists physical status scores between the older and younger groups. The older patients more frequently developed complications than the younger ones, particularly postoperative pneumonia. According to multivariate analyses of all participants, age, chronic obstructive pulmonary disease (COPD), and D2 lymphadenectomy were independent risk factors for postoperative pneumonia. Advanced stage and D2 lymphadenectomy were independent risk factors in the older group, whereas only COPD was an independent risk factor in the younger group.

CONCLUSIONS

LG for gastric cancer can be safely performed in patients aged over 75 years with an acceptable complication rate. However, the present data suggest that care should be taken in selecting LG with D2 lymphadenectomy to treat advanced cancer in these patients because the risk of postoperative complications, especially postoperative pneumonia, increases.

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.

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.

N-acetyl cysteine induces quiescent-like pancreatic stellate cells from an active state and attenuates cancer-stroma interactions

BACKGROUND

Pancreatic stellate cells (PSCs) occupy the majority of the pancreatic cancer microenvironment, contributing to aggressive behavior of pancreatic cancer cells (PCCs). Recently, anti-fibrotic agents have proven to be an effective strategy against cancer, but clinical trials have shown little efficacy, and the driving mechanism remains unknown. N-acetyl-cysteine (NAC) is often used for pulmonary cystic fibrosis. Pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma, was habitually used for type II diabetes, but recently reported to inhibit metastasis of PCCs. However, few studies have focused on the effects of these two agents on cancer-stromal interactions.

METHOD

We evaluated the expression of α-smooth muscle actin (α-SMA) and the number of lipid droplets in PSCs cultured with or without NAC. We also evaluated changes in invasiveness, viability, and oxidative level in PSCs and PCCs after NAC treatment. Using an indirect co-culture system, we investigated changes in viability, invasiveness, and migration of PSCs and PCCs. Combined treatment effects of NAC and Pioglitazone were evaluated in PSCs and PCCs. In vivo, we co-transplanted KPC-derived organoids and PSCs to evaluate the effects of NAC and Pioglitazone's combination therapy on subcutaneous tumor formation and splenic xenografted mouse models.

RESULTS

In vitro, NAC inhibited the viability, invasiveness, and migration of PSCs at a low concentration, but not those of PCCs. NAC treatment significantly reduced oxidative stress level and expression of α-SMA, collagen type I in PSCs, which apparently present a quiescent-like state with a high number of lipid droplets. Co-cultured PSCs and PCCs mutually promoted the viability, invasiveness, and migration of each other. However, these promotion effects were attenuated by NAC treatment. Pioglitazone maintained the NAC-induced quiescent-like state of PSCs, which were reactivated by PCC-supernatant, and enhanced chemosensitivity of PCCs. In vivo, NAC and Pioglitazone's combination suppressed tumor growth and liver metastasis with fewer stromal components and oxidative stress level.

CONCLUSION

NAC suppressed activated PSCs and attenuated cancer-stromal interactions. NAC induces quiescent-like PSCs that were maintained in this state by pioglitazone treatment.

Transuranic nuclides Pu, Am and Cm isotopes, and 90Sr in seafloor sediments off the Fukushima Daiichi Nuclear Power Plant during the period from 2012 to 2019

The ²³⁸Pu, ^239+240Pu, ²⁴¹Am, ²⁴²Cm, ^243+244Cm and ⁹⁰Sr concentrations in seafloor surface sediments collected at three sampling stations off the Fukushima Daiichi Nuclear Power Plant (FDNPP) site during the period from 2012 to 2019 were determined to elucidate the impacts of the FDNPP accident onto their concentrations in coastal sediments and to discuss the sources of the measured radionuclides. The ^239+240Pu, ²⁴¹Pu and ²⁴¹Am concentrations and ²⁴⁰Pu/²³⁹Pu atom ratios in a sediment core were also determined to allow comparison of their inventories between this study and previously reported values and to identify the Pu sources. The ²³⁸Pu, ^239+240Pu, ²⁴¹Am and ⁹⁰Sr concentrations showed no remarkable temporal variations; no significant increases in concentrations after the FDNPP accident were observed; these concentrations were comfortably within the previously reported concentration range; and no detectable ²⁴²Cm and ^243+244Cm amounts were observed in surface sediments. The observed ²³⁸Pu/^239+240Pu activity ratios were approximately two orders of magnitudes lower than those for the damaged FDNPP reactor core inventories and the observed values in terrestrial samples after the accident. The ^239+240Pu, ²⁴¹Pu and ²⁴¹Am inventories in the sediment core were 389 ± 5, 503 ± 33 and 214 ± 3 Bq m^-2, respectively. The ^239+240Pu inventory was about an order of magnitude greater than the expected cumulative deposition density of global fallout from atmospheric nuclear weapons testing due to an enhanced scavenging effect. The ²⁴⁰Pu/²³⁹Pu atom ratios in the sediment core ranged from 0.239 to 0.246 with a mean value of 0.242 ± 0.002; these ratios were clearly greater than the mean global fallout ratio of 0.18. The results for ²³⁸Pu/^239+240Pu activity ratios and ²⁴⁰Pu/²³⁹Pu atom ratios reflected a mixture of global fallout and Pacific Proving Grounds (PPG) close-in fallout Pu rather than Fukushima accident-derived Pu. The sediment column inventory for ^239+240Pu originating from the PPG close-in fallout was calculated as 166 Bq m^-2, which corresponded to 43% of the total inventory. A significant amount of the PPG-derived Pu has been transported by ocean currents and then preferentially scavenged in the coastal waters of Japan.

A rare case of PSA-negative metastasized prostate cancer to the stomach with serum CEA and CA19-9 elevation: a case report

Background

Metastatic cancer to the stomach is relatively rare. Prostate-specific antigen (PSA) is a reliable biomarker used in the screening and management of patients with prostate cancer. However, it is difficult to definitively diagnose a PSA-negative metastatic gastric tumor of prostate cancer because the cancer sometimes resembles primary gastric cancer in clinical images. It is also difficult to distinguish metastatic cancer from primary cancer even in the pathological examination of biopsy samples when the lesion is poorly differentiated adenocarcinoma. There is a possibility that the characteristics of the cancer are changed during treatment such as chemotherapy or radiation therapy. Therefore, careful consideration is required for surgical indication.

Case presentation

A 60-year-old male underwent radical prostatectomy and subsequent radiation therapy for advanced prostate cancer (pT3N1M0) 10 years previously, and hormone therapy was started for metachronous multiple bone metastasis 10 months before. Upper gastrointestinal endoscopy revealed an irregular depressed lesion with a convergence of folds at the greater curvature of the upper gastric body. Biopsy showed poorly differentiated adenocarcinoma that was negative for PSA upon immunohistochemistry. He had high serum carcinoembryonic antigen (CEA) (946.1 ng/ml) and carbohydrate antigen 19-9 (CA19-9) (465.1 U/ml) levels with no elevation of PSA (0.152 ng/ml). The tumor was diagnosed as primary gastric cancer based on the clinical imaging and pathological examination of the biopsy sample including the PSA staining. Based on the diagnosis, laparoscopic proximal gastrectomy with lymphadenectomy was performed. However, pathological examination of the resected specimen revealed poorly differentiated adenocarcinoma that was positive for other prostate markers such as androgen receptor. Thus, the patient was diagnosed with metastasized prostate cancer to the stomach.

Conclusions

We report a case of metastatic gastric cancer of prostate cancer 10 years after radical prostatectomy. In the present case, it was difficult to diagnose a metastatic gastric tumor of prostate cancer preoperatively, because of its resemblance to primary gastric cancer without PSA expression and no serum PSA elevation. Although a rare case entity, it is important to consider the possibility of a metastatic gastric tumor when the surgical indication is determined in cases with another co-existing cancer.

Thoracoscopic surgery combined with endoscopic creation of a submucosal tunnel for a large complicated esophageal leiomyoma

BACKGROUND

The standard surgical method for symptomatic submucosal tumors (SMTs) or tumors with unclear biological behavior is enucleation. Minimally invasive approaches are usually considered appropriate for surgical enucleation; thus, thoracoscopic and laparoscopic enucleation is performed widely and safely. However, it is sometimes difficult to enucleate large and complicated esophageal tumors using thoracoscopic surgery, and even if rare, there is the risk of requiring thoracotomy or esophagectomy. In the present case, we enucleated a large and complicated leiomyoma safely using a new combined method with endoscopic and thoracoscopic procedures.

CASE PRESENTATION

A 42-year-old woman presented to our hospital for a detailed examination of an abnormal finding in her health check-up chest X-ray images. She complained of upper abdominal pain after eating, and computed tomography revealed an esophageal tumor measuring 60 mm in length surrounding her lower thoracic esophagus. Esophagogastroduodenoscopy revealed a huge complicated SMT at the esophagogastric junction. Cytological examination with endoscopic ultrasound-guided fine-needle aspiration showed that the tumor was a leiomyoma. To enucleate this large and complicated esophageal SMT safely and without damaging the esophageal mucosa, we performed endoscopic and thoracoscopic procedures. We created a submucosal tunnel, endoscopically, and then performed thoracoscopic surgery to enucleate the tumor completely from the esophageal muscularis. Using these combined procedures, we were able to easily mobilize even a complicated tumor of this size from the mucosa and completed the surgery thoracoscopically without difficulty. As a result, the tumor was dissected safely with a minimal defect in the muscularis and without damaging the mucosa. Finally, we closed the defect in the esophageal muscularis with continuous sutures, thoracoscopically, and closed the entry of the submucosal tunnel using clips, endoscopically.

CONCLUSIONS

Using these combined procedures, we safely enucleated a huge complicated esophageal SMT. The increased mobility of the tumor after creating the submucosal tunnel contributed to the minimal defect in the muscular layer and prevented injury to the esophageal mucosa, possibly leading to fewer postoperative complications such as esophageal stenosis and local infection.

Detection of Circulating Tumor DNA in Patients with Pancreatic Cancer Using Digital Next-Generation Sequencing

Circulating tumor DNA (ctDNA) measurements can be used to estimate tumor burden, but avoiding false-positive results is challenging. Herein, digital next-generation sequencing (NGS) is evaluated as a ctDNA detection method. Plasma KRAS and GNAS hotspot mutation levels were measured in 140 subjects, including 67 with pancreatic ductal adenocarcinoma and 73 healthy and disease controls. To limit chemical modifications of DNA that yield false-positive mutation calls, plasma DNA was enzymatically pretreated, after which DNA was aliquoted for digital detection of mutations (up to 384 aliquots/sample) by PCR and NGS. A digital NGS score of two SDs above the mean in controls was considered positive. Thirty-seven percent of patients with pancreatic cancer, including 31% of patients with stages I/II disease, had positive KRAS codon 12 ctDNA scores; only one patient had a positive GNAS mutation score. Two disease control patients had positive ctDNA scores. Low-normal-range digital NGS scores at mutation hotspots were found at similar levels in healthy and disease controls, usually at sites of cytosine deamination, and were likely the result of chemical modification of plasma DNA and NGS error rather than true mutations. Digital NGS detects mutated ctDNA in patients with pancreatic cancer with similar yield to other methods. Detection of low-level, true-positive ctDNA is limited by frequent low-level detection of false-positive mutation calls in plasma DNA from controls.

Neutrophil extracellular traps promote liver micrometastasis in pancreatic ductal adenocarcinoma via the activation of cancer‑associated fibroblasts

Cancer‑associated fibroblasts (CAFs) promote the progression of pancreatic ductal adenocarcinoma (PDAC) via tumor‑stromal interactions. Neutrophil extracellular traps (NETs) are extracellular DNA meshworks released from neutrophils together with proteolytic enzymes against foreign pathogens. Emerging studies suggest their contribution to liver metastasis in several types of cancer. Herein, in order to investigate the role of NETs in liver metastasis in PDAC, the effects of NET inhibitors on spontaneous PDAC mouse models were evaluated. It was demonstrated that DNase I, a NET inhibitor, suppressed liver metastasis. For further investigation, further attention was paid to liver micrometastasis and an experimental liver metastasis mouse model was used that was generated by intrasplenic tumor injection. Furthermore, DNase I also suppressed liver micrometastasis and notably, CAFs accumulated in metastatic foci were significantly decreased in number. In vitro experiments revealed that pancreatic cancer cells induced NET formation and consequently NETs enhanced the migration of hepatic stellate cells, which was the possible origin of CAFs in liver metastasis. On the whole, these results suggest that NETs promote liver micrometastasis in PDAC via the activation of CAFs.

Necroptosis in pancreatic cancer promotes cancer cell migration and invasion by release of CXCL5

Background

Necroptosis is a form of programmed cell death that is accompanied by release of intracellular contents, and reportedly contributes to various diseases. Here, we investigate the significance of necroptosis in pancreatic cancer.

Methods

We used immunohistochemistry and western blot analysis to evaluate expression of the key mediators of necroptosis—receptor-interacting serine/threonine protein kinase 3 (RIP3) and mixed lineage kinase domain-like (MLKL)—in human pancreatic cancer. We also tested the effects of conditioned media (CM) from necroptotic cells on pancreatic cancer cells in Transwell migration and Matrigel invasion assays. Protein array analysis was used to investigate possible mediators derived from necroptotic cells.

Results

RIP3 and MLKL are highly expressed in human pancreatic cancer tissues compared with normal pancreas. MLKL expression was particularly intense at the tumor invasion front. CM derived from necroptotic cells promoted cancer cell migration and invasion, but not CM derived from apoptotic cells. C-X-C motif chemokine 5 (CXCL5) was upregulated in CM derived from necroptotic cells compared with CM derived from control or apoptotic cells. Moreover, expression of the receptor for CXCL5, C-X-C-motif chemokine receptor-2 (CXCR2), was upregulated in pancreatic cancer cells. Inhibition of CXCR2 suppressed cancer cell migratory and invasive behavior enhanced by necroptosis.

Conclusion

These findings indicate that necroptosis at the pancreatic cancer invasion front can promote cancer cell migration and invasion via the CXCL5–CXCR2 axis.

Numerous lymph node metastases in early gastric cancer without preoperatively enlarged lymph nodes: a case report

BACKGROUND

According to the 2018 Japanese gastric cancer treatment guidelines (ver. 5), a reduced extent of lymphadenectomy (D1 or D1+) is indicated for cT1 N0 tumors that do not meet the criteria for endoscopic resection. However, early gastric cancer with multiple lymph node metastases is not unknown, and cases have been reported. We report a case of a patient with early gastric cancer and numerous nodal metastases who underwent laparoscopic proximal gastrectomy based on a preoperative diagnosis of T1 N0.

CASE PRESENTATION

A 69-year-old woman underwent emergent endoscopic hemostasis for massive hematemesis of the stomach, and endoscopic examination showed ulceration with a visible vessel. Pathological biopsy examination of the ulcer identified poorly differentiated adenocarcinoma with signet ring cells. The patient was diagnosed with early gastric cancer that was not indicated for endoscopic resection because of the ulceration and histological type. Endoscopic ultrasound showed that the third layer was poorly demarcated at the ulcer scar, indicating invasion to the submucosal layer. Computed tomography did not reveal enlarged lymph nodes or distant metastasis. The preoperative diagnosis was early gastric cancer of the fundus without nodal metastasis, and laparoscopic proximal gastrectomy with D1+ lymphadenectomy was performed. The initial postoperative pathological diagnosis was intramucosal carcinoma without lymphovascular invasion; however, the presence of 26 lymph node metastases was revealed unexpectedly. Additional pathological examination of more resected specimens transected every 2-3 mm revealed that only one lesion contained a small number of cancer cells in the lymphatic duct below the muscularis mucosa.

CONCLUSIONS

We report a case of early gastric cancer with 26 nodal metastases in which lymph node involvement was not identified prior to surgery. These findings indicate that the extent of lymphadenectomy and the surgical procedure should be carefully decided even in cT1 N0 early gastric cancer when several risk factors for lymph node metastasis are present.

Certified Reference Material for Analytical Quality Assurance of Minor and Trace Elements in Food and Related Matrixes Based on a Typical Japanese Diet: Interlaboratory Study

A Certified Reference Material (CRM) was prepared at the National Institute for Environmental Studies (NIES), Japan, in collaboration with the National Institute of Radiological Sciences (NIRS), Japan, for the analytical quality assurance of minor and trace elements in food and related matrixes. The starting material for the CRM was all food served in 29 households in Japan over two 3-day periods in 1997–1998, and thus the CRM represented a typical Japanese diet. All foods (meals, snacks, and beverages) were homogenized, freeze-dried, pulverized, blended, dispensed into 1100 bottles, and sterilized. The within- and between-bottle homogeneity of the prepared CRM was satisfactory for most of the elements. The concentrations of 14 elements (Na, Mg, K, Ca, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Ba, and U) were certified based on a collaborative analysis involving NIES, NIRS, and 20 other laboratories. Reference values were given for the concentrations of 12 additional elements (P, Cl, Fe, Co, Ni, Br, Rb, Mo, I, Cs, Pb, and Th). The elements certified and those given reference values include minerals, essential trace elements, contaminant elements, and long-lived radionuclides. Thus, this CRM is of practical value in the quality assurance of element analysis of foods and diets in nutritional, environmental, and radiological research.

Inhibition of ERK1/2 in cancer-associated pancreatic stellate cells suppresses cancer-stromal interaction and metastasis

Background

Extracellular signal-regulated kinases (ERKs) have been related to multiple cancers, including breast cancer, hepatocellular cancer, lung cancer and colorectal cancer. ERK1/2 inhibitor can suppress growth of KRAS-mutant pancreatic tumors by targeting cancer cell. However, no studies have shown the expression of ERK1/2 on pancreatic stromal and its effect on pancreatic cancer–stromal interaction.

Methods

Immunohistochemistry and western blotting were performed to detect the expression of p-ERK1/2 in pancreatic tissues and cells. Cell viability assay was used to study IC50 of ERK inhibitor on pancreatic cancer cells (PCCs) and primary cancer-associated pancreatic stellate cells (PSCs). Transwell migration, invasion, cell viability assay, senescence β-galactosidase staining were performed to determine the effect of ERK inhibitor on PCCs and PSCs in vitro and in vivo. The expression of key factors involved in autophagy and epithelial-to-mesenchymal transition (EMT) process were evaluated by western blotting. The expression of key factors related to cell invasiveness and malignancy were confirmed by qRT-PCR. Co-transplantation of PCC Organoid and PSC using a splenic xenograft mouse model was used to evaluated combined treatment of ERK inhibitor and autophagy inhibitor.

Results

Immunohistochemical staining in pancreatic tumor samples and transgenetic mice detected p-ERK1/2 expression in both cancer cells and stromal cells. In pancreatic tissues, p-ERK1/2 was strongly expressed in cancer-associated PSCs compared with cancer cells and normal PSCs. PSCs were also significantly more sensitive to ERK1/2 inhibitor treatment. Inhibition of ERK1/2 suppressed EMT transition in HMPCCs, upregulated cellular senescence markers, activated autophagy in cancer-associated PSCs; and suppressed cancer–stromal interaction, which enhanced invasiveness and viability of cancer cells. We also found that chloroquine, an autophagy inhibitor, suppressed ERK inhibition-induced autophagy and promoted PSC cellular senescence, leading to significantly decreased cell proliferation. The combination of an ERK inhibitor and autophagy inhibitor suppressed liver metastasis in a splenic pancreatic cancer organoid xenograft mouse model.

Conclusions

These data indicate that inhibition of ERK1/2 in cancer-associated pancreatic stellate cells suppresses cancer–stromal interaction and metastasis.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1226-8) contains supplementary material, which is available to authorized users.

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.

CD110 promotes pancreatic cancer progression and its expression is correlated with poor prognosis

PURPOSE

This study aimed at investigating the function and significance of CD110 expression in pancreatic cancer.

METHODS

We performed immunohistochemical staining for CD110 expression in tumor samples from 86 patients with pancreatic cancer. We evaluated clinical outcomes and other clinicopathological factors to determine the significance of CD110 on survival and liver metastasis. We examine thrombopoietin-CD110 signaling in cancer cell extravasation in vitro and in vivo. We investigated the effects of CD110 knockdown on liver metastasis in a splenic xenograft mouse model.

RESULTS

CD110 expression in cancer cells was associated with low-histological-grade invasive ductal carcinoma, and patients with high CD110 expression had poorer prognosis (P = 0.0003). High CD110 expression was an independent predictor of liver metastasis (P = 0.0422). Knockdown of CD110 expression significantly attenuated cell migration and invasion. Treatment with thrombopoietin promoted pancreatic cancer cell extravasation. In the presence of thrombopoietin, CD110 increased cell viability through the activation of the ERK-MYC signaling pathway. Knockdown of CD110 expression inhibited liver metastases in the mouse model.

CONCLUSIONS

CD110 promotes pancreatic cancer progression and it may serve as a predictive factor for liver metastasis.

Cancer-associated acinar-to-ductal metaplasia within the invasive front of pancreatic cancer contributes to local invasion

The pancreas is an organ prone to inflammation, fibrosis, and atrophy because of an abundance of acinar cells that produce digestive enzymes. A characteristic of pancreatic cancer is the presence of desmoplasia, inflammatory cell infiltration, and cancer-associated acinar atrophy (CAA) within the invasive front. CAA is characterized by a high frequency of small ducts and resembles acinar-to-ductal metaplasia (ADM). However, the clinical significance of changes in acinar morphology, such as ADM with acinar atrophy, within the tumor microenvironment remains unclear. Here, we find that ADM within the invasive front of tumors is associated with cell invasion and desmoplasia in an orthotopic mouse model of pancreatic cancer. An analysis of resected human tumors revealed that regions of cancer-associated ADM were positive for TGFα, and that this TGFα expression was associated with primary tumor size and shorter survival times. Gene expression analysis identified distinct phenotypic profiles for cancer-associated ADM, sporadic ADM and chronic pancreatitis ADM. These findings suggest that the mechanisms driving ADM differ according to the specific tissue microenvironment and that cancer-associated ADM and acinar atrophy contribute to tumor cell invasion of the local pancreatic parenchyma.

Genetic assessment of recurrent pancreatic high-risk lesions in the remnant pancreas: Metachronous multifocal lesion or local recurrence?

BACKGROUND

It is difficult to determine whether a second high-risk lesion, including pancreatic ductal adenocarcinoma or high-grade pancreatic intraepithelial neoplasm, is a metachronous multifocal lesion or represents local recurrence after resection of the first high-risk lesion. This study attempts to clarify the characteristics of second high-risk lesions in the remnant pancreas using genetic analyses.

METHODS

Clinicopathologic data were collected from 12 patients who underwent pancreatectomy for a second high-risk lesion in the remnant pancreas. We performed mutational and immunohistochemical analyses of 4 major genes-KRAS, TP53, CDKN2A, and SMAD4-associated with pancreatic ductal adenocarcinoma progression, as well as targeted next-generation sequencing.

RESULTS

Mutations in the four genes in the second high-risk lesion were consistent with the first lesion in four patients but were inconsistent in the remaining eight patients, and thus we considered that the latter eight patients likely had metachronous multifocal high-risk lesions and the other four patients had local recurrence. The estimated cumulative recurrence rate after resection of the second high-risk lesion was greater in the local recurrence group compared with the metachronous multifocal group, and the estimated cumulative disease-specific survival rate was greater in the metachronous multifocal group. Targeted next-generation sequencing demonstrated that the second lesions in the metachronous multifocal high-risk lesion group showed differences in founder mutations compared with the first lesion. In the local recurrence group, the founder mutations in the second lesion were common with those in the first lesion.

CONCLUSION

Genetic assessment might help discriminate metachronous multifocal high-risk lesions from local recurrence.

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.

Pancreatic Juice Mutation Concentrations Can Help Predict the Grade of Dysplasia in Patients Undergoing Pancreatic Surveillance

Purpose: The measurement of mutations in pancreatic juice samples collected from the duodenum during endoscopic ultrasound (EUS) may improve the diagnostic evaluation of patients undergoing pancreatic surveillance. Our aim was to evaluate the accuracy of using pancreatic juice mutation concentrations to predict the presence and histologic grade of neoplasia in the pancreas.Experimental Design: Digital next-generation sequencing (NGS) of pancreatic juice DNA using a targeted 12-gene panel was performed on 67 patients undergoing pancreatic evaluation during EUS, including patients with pancreatic ductal adenocarcinoma, patients who subsequently underwent pancreatic resection for precursor lesions, patients undergoing surveillance for their familial/inherited susceptibility to pancreatic cancer, and normal pancreas disease controls.Results: Patients with pancreatic cancer or high-grade dysplasia as their highest grade lesion had significantly higher pancreatic juice mutation concentrations than all other subjects (mean/SD digital NGS score; 46.6 ± 69.7 vs. 6.2 ± 11.6, P = 0.02). Pancreatic juice mutation concentrations distinguished patients with pancreatic cancer or high-grade dysplasia in their resection specimen from all other subjects with 72.2% sensitivity and 89.4% specificity [area under the curve (AUC) = 0.872]. Mutant TP53/SMAD4 concentrations could distinguish patients with pancreatic cancer or high-grade dysplasia in their resection specimen from all other subjects with 61.1% sensitivity and 95.7% specificity (AUC = 0.819). Among 31 high-risk individuals under surveillance, 2 of the 3 individuals with most abnormal pancreatic juice mutation profiles also had the most abnormalities on pancreatic imaging.Conclusions: Pancreatic juice mutation analysis using digital NGS has potential diagnostic utility in the evaluation of patients undergoing pancreatic surveillance. Clin Cancer Res; 24(12); 2963-74. ©2018 AACRSee related commentary by Lipner and Yeh, p. 2713.

Digital next-generation sequencing identifies low-abundance mutations in pancreatic juice samples collected from the duodenum of patients with pancreatic cancer and intraductal papillary mucinous neoplasms

OBJECTIVE

Secretin-stimulated pancreatic juice contains DNA shed from cells lining the pancreatic ducts. Genetic analysis of this fluid may form a test to detect pancreatic ductal neoplasia.

DESIGN

We employed digital next-generation sequencing ('digital NGS') to detect low-abundance mutations in secretin-stimulated juice samples collected from the duodenum of subjects enrolled in Cancer of the Pancreas Screening studies at Johns Hopkins Hospital. For each juice sample, digital NGS necessitated 96 NGS reactions sequencing nine genes. The study population included 115 subjects (53 discovery, 62 validation) (1) with pancreatic ductal adenocarcinoma (PDAC), (2) intraductal papillary mucinous neoplasm (IPMN), (3) controls with non-suspicious pancreata.

RESULTS

Cases with PDAC and IPMN were more likely to have mutant DNA detected in pancreatic juice than controls (both p<0.0001); mutant DNA concentrations were higher in patients with PDAC than IPMN (p=0.003) or controls (p<0.001). TP53 and/or SMAD4 mutations were commonly detected in juice samples from patients with PDAC and were not detected in controls (p<0.0001); mutant TP53/SMAD4 concentrations could distinguish PDAC from IPMN cases with 32.4% sensitivity, 100% specificity (area under the curve, AUC 0.73, p=0.0002) and controls (AUC 0.82, p<0.0001). Two of four patients who developed pancreatic cancer despite close surveillance had SMAD4/TP53 mutations from their cancer detected in juice samples collected over 1 year prior to their pancreatic cancer diagnosis when no suspicious pancreatic lesions were detected by imaging.

CONCLUSIONS

The detection in pancreatic juice of mutations important for the progression of low-grade dysplasia to high-grade dysplasia and invasive pancreatic cancer may improve the management of patients undergoing pancreatic screening and surveillance.

IL2RG, identified as overexpressed by RNA-seq profiling of pancreatic intraepithelial neoplasia, mediates pancreatic cancer growth

Pancreatic ductal adenocarcinoma evolves from precursor lesions, the most common of which is pancreatic intraepithelial neoplasia (PanIN). We performed RNA-sequencing analysis of laser capture microdissected PanINs and normal pancreatic duct cells to identify differentially expressed genes between PanINs and normal pancreatic duct, and between low-grade and high-grade PanINs. One of the most highly overexpressed transcripts identified in PanIN is interleukin-2 receptor subunit gamma (IL2RG) encoding the common gamma chain, IL2Rγ. CRISPR-mediated knockout of IL2RG in orthotopically implanted pancreatic cancer cells resulted in attenuated tumor growth in mice and reduced JAK3 expression in orthotopic tumors. These results indicate that IL2Rγ/JAK3 signaling contributes to pancreatic cancer cell growth in vivo.

Deleterious Germline Mutations in Patients With Apparently Sporadic Pancreatic Adenocarcinoma

Purpose Deleterious germline mutations contribute to pancreatic cancer susceptibility and are well documented in families in which multiple members have had pancreatic cancer. Methods To define the prevalence of these germline mutations in patients with apparently sporadic pancreatic cancer, we sequenced 32 genes, including known pancreatic cancer susceptibility genes, in DNA prepared from normal tissue obtained from 854 patients with pancreatic ductal adenocarcinoma, 288 patients with other pancreatic and periampullary neoplasms, and 51 patients with non-neoplastic diseases who underwent pancreatic resection at Johns Hopkins Hospital between 2000 and 2015. Results Thirty-three (3.9%; 95% CI, 3.0% to 5.8%) of 854 patients with pancreatic cancer had a deleterious germline mutation, 31 (3.5%) of which affected known familial pancreatic cancer susceptibility genes: BRCA2 (12 patients), ATM (10 patients), BRCA1 (3 patients), PALB2 (2 patients), MLH1 (2 patients), CDKN2A (1 patient), and TP53 (1 patient). Patients with these germline mutations were younger than those without (mean ± SD, 60.8 ± 10.6 v 65.1 ± 10.5 years; P = .03). Deleterious germline mutations were also found in BUB1B (1) and BUB3 (1). Only three of these 33 patients had reported a family history of pancreatic cancer, and most did not have a cancer family history to suggest an inherited cancer syndrome. Five (1.7%) of 288 patients with other periampullary neoplasms also had a deleterious germline mutation. Conclusion Germline mutations in pancreatic cancer susceptibility genes are commonly identified in patients with pancreatic cancer without a significant family history of cancer. These deleterious pancreatic cancer susceptibility gene mutations, some of which are therapeutically targetable, will be missed if current family history guidelines are the main criteria used to determine the appropriateness of gene testing.

Feasibility and safety of modified inverted T-shaped method using linear stapler with movable cartridge fork for esophagojejunostomy following laparoscopic total gastrectomy

BACKGROUND

We previously reported the use of an inverted T-shaped method to obtain a suitable view for hand sewing to close the common entry hole when the linear stapler was fired for esophagojejunostomy after laparoscopic total gastrectomy (LTG). This conventional method involved insertion of the fixed cartridge fork to the Roux limb and the fine movable anvil fork to the esophagus to avoid perforation of the jejunum. However, insertion of the movable anvil fork to the esophagus during this procedure often requires us to strongly push down the main body of the stapler with the fixed cartridge fork to bring the direction of the anvil fork in line with the direction of the long axis of the esophagus while controlling the opening of the movable anvil fork. We therefore modified this complicated inverted T-shaped method using a linear stapler with a movable cartridge fork. This modified method involved insertion of the movable cartridge fork into the Roux limb followed by natural, easy insertion of the fixed anvil fork into the esophagus without controlling the opening of the movable cartridge fork.

METHODS

We performed LTG in a total of 155 consecutive patients with gastric cancer from November 2007 to December 2015 in Kyushu University Hospital. After LTG, we performed the conventional inverted T-shaped method using a linear stapler with a fixed cartridge fork in 61 patients from November 2007 to July 2011 (fixed cartridge group). From August 2011, we used a linear stapler with a movable cartridge fork and performed the modified inverted T-shaped method in 94 patients (movable cartridge group). We herein compare the short-term outcomes in 94 cases of LTG using the modified method (movable cartridge fork) with those in 61 cases using the conventional method (fixed cartridge fork).

RESULTS

We found no significant differences in the perioperative or postoperative events between the movable and fixed cartridge groups. One case of anastomotic leakage occurred in the fixed cartridge group, but no anastomotic leakage occurred in the movable cartridge group.

CONCLUSIONS

Although there were no remarkable differences in the short-term outcomes between the movable and fixed cartridge groups, we believe that the modified inverted T-shaped method is technically more feasible and reliable than the conventional method and will contribute to the improved safety of LTG.

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.

Lack of association between the pancreatitis risk allele CEL-HYB and pancreatic cancer

CEL-HYB is a hybrid allele that arose from a crossover between the 3’ end of the Carboxyl ester lipase (CEL) gene and the nearby CEL pseudogene (CELP) and was recently identified as a risk factor for chronic pancreatitis. Since chronic pancreatitis is a risk factor for the development of pancreatic cancer, we compared the prevalence of the CEL-HYB allele in patients with pancreatic ductal adenocarcinoma to spousal controls and disease controls. The CEL-HYB allele was detected using Sanger and next generation sequencing. There was no significant difference in the prevalence of the CEL-HYB allele between cases with pancreatic ductal adenocarcinoma compared to controls; 2.6% (22/850) vs. 1.8% (18/976) (p=0.35). CEL-HYB carriers were not more likely to report a history of pancreatitis. Patients with pancreatic cancer are not more likely than controls to be carriers of the CEL-HYB allele.

Obstructive Sleep Apnea and Pathological Characteristics of Resected Pancreatic Ductal Adenocarcinoma

BACKGROUND

Prospective studies have identified obstructive sleep apnea (OSA) as a risk factor for increased overall cancer incidence and mortality. The potential role of OSA in the risk or progression of specific cancers is not well known. We hypothesized that pathological differences in pancreatic cancers from OSA cases compared to non-OSA cases would implicate OSA in pancreatic cancer progression.

METHODS

We reviewed the medical records of 1031 patients who underwent surgical resection without neoadjuvant therapy for pancreatic ductal adenocarcinoma (PDAC) at Johns Hopkins Hospital between 2003 and 2014 and compared the TNM classification of their cancer and their overall survival by patient OSA status.

RESULTS

OSA cases were significantly more likely than non-OSA cases to have lymph node-negative tumors (37.7% vs. 21.8%, p = 0.004). Differences in the prevalence of nodal involvement of OSA vs. non-OSA cases were not associated with differences in other pathological characteristics such as tumor size, tumor location, resection margin status, vascular or perineural invasion, or other comorbidities more common to OSA cases (BMI, smoking, diabetes). A logistic regression model found that a diagnosis of OSA was an independent predictor of lymph node status (hazard ratio, 0.051, p = 0.038). Patients with OSA had similar overall survival compared to those without OSA (HR, 0.89, (0.65-1.24), p = 0.41).

CONCLUSION

The observed pathological differences between OSA-associated and non-OSA-associated pancreatic cancers supports the hypothesis that OSA can influence the pathologic features of pancreatic ductal adenocarcinoma.

Expression of glucose transporter-1 is correlated with hypoxia-inducible factor 1α and malignant potential in pancreatic neuroendocrine tumors

The present study aimed to investigate the prognostic usefulness of the expression of glucose transporter type 1 (GLUT-1) and GLUT-2, hypoxia-inducible factor 1α (HIF-1α) and insulin-like growth factor II messenger RNA-binding protein 3 (IMP3) in pancreatic neuroendocrine tumors (pNETs). Immunohistochemical staining for GLUT-1, GLUT-2, HIF-1α and IMP3 was performed in 70 pNET specimens. The expression of GLUT-1 and HIF-1α was significantly higher in the World Health Organization grade 2 (G2), neuroendocrine carcinoma cases and mixed-type pNETs compared with the G1 cases. Vessel invasion, a high Ki-67 labeling index and a high mitotic count were significantly more frequent in the GLUT-1- and HIF-1α-positive cases compared with the negative cases. Lymph node metastasis was significantly higher in the GLUT-1-positive cases than in the negative cases. Insulin expression was significantly higher in the IMP3-positive cases than the negative cases. The GLUT-1 expression group experienced a significantly poor disease-free survival rate compared with the negative GLUT-1 expression group. HIF-1α expression was significantly correlated with poor disease-free survival and overall survival rates. A multivariate analysis revealed that lymph node metastasis was an independent risk factor for disease-free survival in all cases. In the G1/G2 group, tumor size and lymph node metastasis were independent risk factors for disease-free survival. Overall, the results suggested that GLUT-1 is a useful prognostic biomarker for pNETs.

TM4SF1 as a prognostic marker of pancreatic ductal adenocarcinoma is involved in migration and invasion of cancer cells

The cell surface protein Transmembrane 4 L6 family member 1 (TM4SF1) has been detected in various tumors, and its expression on tumor cells is implicated in cancer cell metastasis and patient prognosis. The role of TM4SF1 in malignant tumors remains poorly understood, particularly in pancreatic cancer. We performed immunohistochemical staining to analyze the expression of TM4SF1 in resected pancreatic tissues and investigated the correlation between TM4SF1 expression and prognosis. The function of TM4SF1 in the invasion and migration of pancreatic cancer cells was analyzed in vitro using an RNA interference technique. In pancreatic cancer tissues, TM4SF1 expression was detected in cancer cells, and patients with high tumor levels of TM4SF1 showed longer survival times than those with low TM4SF1 levels (P=0.0332). In vitro, reduced TM4SF1 expression enhanced the migration (P<0.05) and invasion (P<0.05) of pancreatic cancer cells partially via decreased E-cadherin expression. TM4SF1 protein levels were also reduced after TGF-β1-induced epithelial-mesenchymal transition (EMT).TM4SF1 expression is associated with better prognosis in pancreatic cancer. Loss of TM4SF1 contributes to the invasion and migration of pancreatic cancer cells.

Anterior gradient 2 downregulation in a subset of pancreatic ductal adenocarcinoma is a prognostic factor indicative of epithelial-mesenchymal transition

Anterior gradient 2 (AGR2), a member of the protein disulfide isomerase family, has been implicated in various cancers including pancreatic ductal adenocarcinoma (PDAC) and is known to promote cancer progression. However, the prognostic value of AGR2 expression and the interaction with epithelial-mesenchymal transition (EMT) remain unclear. We investigated the clinical significance of AGR2 and EMT markers in PDAC patients by immunohistochemical analyses. Although AGR2 expression was not observed in normal pancreas, all pancreatic precursor neoplastic lesions were positive for AGR2, even at the earliest stages, including pancreatic intraepithelial neoplasia-1A, AGR2 expression was reduced in 27.7% (54/195 cases) of PDAC patients. AGR2 downregulation correlated with EMT markers (vimentin overexpression and reduced membranous E-cadherin expression), high Union for International Cancer Control stage (P<0.0001), high histological cellular grade (P<0.0001), and adverse outcome (P<0.0001). In vitro, targeted silencing of AGR2 in cancer cells using siRNA reduced cell proliferation, colony formation, cell invasiveness, and migration, but did not alter EMT markers. To confer a more aggressive phenotype and induce EMT in PDAC cells, we co-cultured PDAC cell lines with primary-cultured pancreatic stellate cells (PSCs) and found that AGR2 was downregulated in co-cultured PDAC cells compared with PDAC monocultures. Treatment with transforming growth factor beta-1 (TGF-β), secreted from PSCs, decreased AGR2 expression, whereas inhibition of TGF-β signaling using recombinant soluble human TGF-β receptor type II and TGF-β-neutralizing antibodies restored AGR2 expression. We conclude that AGR2 downregulation is a useful prognostic marker, induced by EMT, and that secreted TGF-β from PSCs may partially contribute to AGR2 downregulation in PDAC patients. AGR2 downregulation does not induce EMT or a more aggressive phenotype, but is a secondary effect of these processes in advanced PDAC.