Clinicopathologic and immunohistochemical characteristics of gastric adenocarcinoma with enteroblastic differentiation: a study of 29 cases

BACKGROUND

Gastric adenocarcinoma with enteroblastic differentiation (GAED) has been recognized as a variant of alpha-fetoprotein (AFP)-producing gastric carcinoma, although its clinicopathologic and immunohistochemical features have not been fully elucidated.

METHODS

To elucidate the clinicopathologic and immunohistochemical features of GAED, we analyzed 29 cases of GAED, including ten early and 19 advanced lesions, and compared these cases with 100 cases of conventional gastric adenocarcinoma (CGA). Immunohistochemistry for AFP, glypican 3, SALL4, and p53 was performed, and the phenotypic expression of the tumors was evaluated by immunostaining with antibodies against MUC5AC, MUC6, MUC2, CD10, and caudal-type homeobox 2 (CDX2).

RESULTS

Lymphatic and venous invasion was more frequent in GAED (76 and 72 %) than in CGA (41 and 31 %; P ≤ 0.001). Lymph node metastasis was more frequently observed in GAED (69 %) than in CGA (38 %; P = 0.005), as were synchronous or metachronous liver metastases (GAED, 31 %; CGA, 6 %; P ≤ 0.001). Immunohistochemically, all GAED were positive for at least one of three enteroblastic linage markers (AFP, glypican 3, and SALL4). Glypican 3 was the most sensitive marker (83 %) for GAED, followed by SALL4 (72 %) and AFP (45 %), whereas no CGA was positive. Furthermore, the rate of positive p53 staining was 59 % in GAED. Regarding the mucin phenotype, CD10 and CDX2 were diffusely or focally expressed in all GAED cases. Invasive areas with hepatoid or enteroblastic differentiation were negative for CD10 and CDX2.

CONCLUSIONS

Clinicopathologic features of GAED differ from those of CGA. GAED shows aggressive biological behavior, and is characteristically immunoreactive to AFP, glypican 3, or SALL4.

Long-term Outcomes After Endoscopic Submucosal Dissection for Large Colorectal Epithelial Neoplasms: A Prospective, Multicenter, Cohort Trial From Japan

BACKGROUND & AIMS

To determine the long-term outcomes after colorectal endoscopic submucosal dissection (ESD), we conducted a large, multicenter, prospective cohort trial with a 5-year observation period.

METHODS

Between February 2013 and January 2015, we consecutively enrolled 1740 patients with 1814 colorectal epithelial neoplasms ≥20 mm who underwent ESD. Patients with noncurative resection (non-CR) lesions underwent additional radical surgery, as needed. After the initial treatment, intensive 5-year follow-up with planned multiple colonoscopies was conducted to identify metastatic and/or local recurrences. Primary outcomes were overall survival, disease-specific survival, and intestinal preservation rates. The rates of local recurrence and metachronous invasive cancer were evaluated as the secondary outcomes.

RESULTS

The 5-year overall survival, disease-specific survival, and intestinal preservation rates were 93.6%, 99.6%, and 88.6%, respectively. Patients with CR lesions had no metastatic occurrence, and patients with non-CR lesions had 4 metastatic occurrences. Kaplan-Meier curves revealed that overall survival and disease-specific survival rates were significantly higher in patients with CR lesions than in those with non-CR lesions (P > .001 and P = .009, respectively). Local recurrence occurred in only 8 lesions (0.5%), which were successfully resected by subsequent endoscopic treatment. Multiple logistic regression analyses revealed that piecemeal resection (hazard ratio, 8.19; 95% CI, 1.47-45.7; P = .02) and margin-positive resection (hazard ratio, 8.06; 95% CI, 1.76-37.0; P = .007) were significant independent predictors of local recurrence after colorectal ESD. Fifteen metachronous invasive cancers (1.0%) were identified during surveillance colonoscopy, most of which required surgical resection.

CONCLUSIONS

A favorable long-term prognosis indicates that ESD can be the standard treatment for large colorectal epithelial neoplasms.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000010136.

Next-generation sequencing analysis for gastric adenocarcinoma with enteroblastic differentiation: emphasis on the relationship with hepatoid adenocarcinoma

Histologically tubulopapillary structures with glycogen-rich clear cytoplasm in gastric adenocarcinoma with enteroblastic differentiation (GAED) are well known, but a solid growth pattern can also be observed as a minor component. In contrast, hepatoid adenocarcinoma (HAC) of the stomach shows many overlapping features, including solid pattern and α-fetoprotein expression. In this study, we employed next-generation sequencing (NGS) to establish a molecular/clinicopathological concept of GAED and clarify whether these two tumors should be grouped together in one category. Among 2273 primary gastric cancers treated in our hospital between 2008 and 2017, we defined 51 cases as GAEDs showing tubulopapillary or solid patterns that express at least one of the following markers: α-fetoprotein, glypican-3, or spalt-like transcription factor 4. All cases previously diagnosed as HAC in our hospital had clear cytoplasm and were included as GAEDs by histological re-evaluation and immunohistochemical findings. We performed NGS for 24 histologically typical GAEDs and Sanger sequencing for the remaining cases. The most frequently mutated gene was TP53, and almost all cases with missense mutation showed p53 overexpression. An analysis of copy number variation revealed that ERBB2 amplification was the most frequent in GAED. Additionally, HER2 immunohistochemistry and fluorescence in situ hybridization confirmed that 22% of informative cases were HER2 positive. There was no correlation between molecular/clinicopathological parameters and α-fetoprotein expression or growth patterns in GAED. Our analysis showed that GAED frequently harbors TP53 mutations and ERBB2 amplification. As with conventional gastric adenocarcinoma, trastuzumab may be effective for GAED. Furthermore, HAC may be subcategorized as a solid-type GAED.

Closure with clips to accelerate healing of mucosal defects caused by colorectal endoscopic submucosal dissection

BACKGROUND

Most mucosal defects that occur with endoscopic submucosal dissection (ESD) can be closed completely using endoscopic clips. However, benefits of such closure in wound healing are unknown. A randomized controlled study evaluated the efficacy of closure with clips compared with no closure.

METHOD

Twenty-eight patients who had undergone ESD were randomly divided into two groups: closure (n = 14) and non-closure groups (n = 14). In the closure group, the mucosal defect resulting from ESD was closed using endoscopic clips. Four weeks after ESD, defects in both groups were observed by colonoscopy. Efficacy was based on change in the area of the defect, percentage of complete healing in each group, and complications.

RESULT

Data were analyzed for 26 of the 28 patients (13, closure group; 13, non-closure group). All tumors were resected en bloc by ESD without bleeding or perforation. In the closure group, the area of the defect just after ESD was 677 ± 306 mm(2) (mean ± SD) as determined by the size of the removed lesion and had decreased to 2.17 ± 4.51 mm(2) at 4 weeks after ESD (reduction, 99.7 %), but in the non-closure group that area was 790 ± 221 mm(2) and had decreased to 27.42 ± 25.72 mm(2) at 4 weeks post-ESD (reduction, 96.2 %). The reduction rate was significantly higher in the closure than in the non-closure group (99.7 vs. 96.2 %, p = 0.010). Complete healing was 69.2 % in the closure group vs. 7.7 % in the non-closure group (p = 0.005). Multivariate analysis showed that closure of the mucosal defect (OR 24.029, 95 % CI 2.09-276.15, p = 0.011) was an independent factor associated with complete healing at 4 weeks after ESD. Delayed perforation or post-ESD bleeding was not observed in any participant.

CONCLUSION

Use of endoscopic clips for closure of defects after ESD is safe and efficacious in accelerating wound healing.

TRIAL REGISTRATION

UMIN-CTR UMIN000009112.

Distinct endoscopic characteristics of sessile serrated adenoma/polyp with and without dysplasia/carcinoma

BACKGROUND AND AIMS

Sessile serrated adenoma/polyp (SSA/P) is a colorectal polyp that has malignant potential. However, the dysplastic components within an SSA/P can be difficult to detect. This study aimed to clarify the endoscopic characteristics of SSA/P with advanced histology.

METHODS

We examined 462 endoscopically or surgically resected lesions that were pathologically diagnosed as SSA/P, including 414 without and 41 with cytologic dysplasia, and 7 with invasive carcinoma. We retrospectively studied the clinicopathologic and endoscopic characteristics and performed pit pattern analysis.

RESULTS

A stepwise increase in the size of the SSA/P series was identified along with their dysplastic progression, although 19 of 48 (39.6%) SSA/Ps with dysplasia/carcinoma were ≤10 mm in size. Most lesions were covered with a mucus cap. Macroscopically, (semi)pedunculated morphology, double elevation, central depression, and reddishness were found more frequently in SSA/P with cytologic dysplasia and invasive carcinoma ([semi]pedunculated morphology, 17.1%/28.6%; double elevation, 63.4%/57.1%; central depression, 9.8%/28.6%; reddishness, 39.0%/85.7%) than in those without dysplasia (4.6%, 4.6%, 3.9%, and 3.4%, respectively). Furthermore, the presence of at least 1 of these 4 markers had high sensitivity (91.7%) for identifying the dysplasia/carcinoma within a SSA/P, with a specificity of 85.3%. In the pit pattern analysis, all SSA/Ps without dysplasia exhibited type II pit pattern only, whereas 94.4% of SSA/Ps with dysplasia/carcinoma showed type II in addition to type III_L, IV, V_I, or V_N pit patterns.

CONCLUSIONS

In an SSA/P series, endoscopic characteristics, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, in addition to the use of magnifying endoscopy, may be useful to accurately diagnose advanced histology within an SSA/P.

Molecular characterization of sessile serrated adenoma/polyps with dysplasia/carcinoma based on immunohistochemistry, next-generation sequencing, and microsatellite instability testing: a case series study

Background

Colorectal sessile serrated adenoma/polyps (SSA/Ps) are considered early precursor lesions in the serrated neoplasia pathway. Recent studies have shown associations of SSA/Ps with lost MLH1 expression, a CpG island methylator phenotype, and BRAF mutations. However, the molecular biological features of SSA/Ps with early neoplastic progression have not yet been fully elucidated, owing to the rarity of cases of SSA/P with advanced histology such as cytologic dysplasia or invasive carcinoma. In this study, we aimed to elucidate the molecular biological features of SSA/Ps with dysplasia/carcinoma, representing relatively early stages of the serrated neoplasia pathway.

Methods

We performed immunostaining for β-catenin, MLH1, and mucins (e.g., MUC2, MUC5AC, MUC6, and CD10); targeted next-generation sequencing; and microsatellite instability (MSI) testing in 8 SSA/P lesions comprised of 4 SSA/Ps with high-grade dysplasia and 4 SSA/Ps with submucosal carcinoma.

Results

Lost MLH1 expression was found in 5 cases. All lesions studied were positive for nuclear β-catenin expression. Regarding phenotypic mucin expression, all lesions were positive for MUC2, but negative for CD10. MUC5AC and MUC6 positivity was observed in 7 cases. Genetically, the most frequently mutated gene was BRAF (7 cases), and other mutations were detected in FBXW7 (3 cases); TP53 (2 cases), and KIT, PTEN, SMAD4, and SMARCB1 (1 case each). Furthermore, 4 of 8 lesions were MSI-high and the remaining 4 lesions were microsatellite-stable (MSS). Interestingly, all 4 MSI-high lesions displayed MLH1 loss, 3 of which harbored a FBXW7 mutation, but not a TP53 mutation. However, 2 MSS lesions harbored a TP53 mutation, although none harbored a FBXW7 mutation.

Conclusions

SSA/Ps with dysplasia/carcinoma frequently harbored BRAF mutations. Activation of the WNT/β-catenin signaling pathway may facilitate the development of dysplasia in SSA/Ps and progression to carcinoma. Furthermore, our results suggested that these lesions might be associated with both MSI-high and MSS colorectal cancer, which might be distinguished by distinct molecular biological features such as lost MLH1 expression, FBXW7 mutations, and TP53 mutations.

Clinicopathological features of alpha-fetoprotein producing early gastric cancer with enteroblastic differentiation

AIM

To investigate clinicopathological features of early stage gastric cancer with enteroblastic differentiation (GCED).

METHODS

We retrospectively investigated data on 6 cases of early stage GCED and 186 cases of early stage conventional gastric cancer (CGC: well or moderately differentiated adenocarcinoma) who underwent endoscopic submucosal dissection or endoscopic mucosal resection from September 2011 to February 2015 in our hospital. GCED was defined as a tumor having a primitive intestine-like structure composed of cuboidal or columnar cells with clear cytoplasm and immunohistochemical positivity for either alpha-fetoprotein, Glypican 3 or SALL4. The following were compared between GCED and CGC: age, gender, location and size of tumor, macroscopic type, ulceration, depth of invasion, lymphatic and venous invasion, positive horizontal and vertical margin, curative resection rate.

RESULTS

Six cases (5 males, 1 female; mean age 75.7 years; 6 lesions) of early gastric cancer with a GCED component and 186 cases (139 males, 47 females; mean age 72.7 years; 209 lesions) of early stage CGC were investigated. Mean tumor diameters were similar but rates of submucosal invasion, lymphatic invasion, venous invasion, and non-curative resection were higher in GCED than CGC (66.6% vs 11.4%, 33.3% vs 2.3%, 66.6% vs 0.4%, 83.3% vs 11% respectively, P < 0.01). Deep submucosal invasion was not revealed endoscopically or by preoperative biopsy. Histologically, in GCED the superficial mucosal layer was covered with a CGC component. The GCED component tended to exist in the deeper part of the mucosa to the submucosa by lymphatic and/or venous invasion, without severe stromal reaction. In addition, Glypican 3 was the most sensitive marker for GCED (positivity, 83.3%), immunohistochemically.

CONCLUSION

Even in the early stage GCED has high malignant potential, and preoperative diagnosis is considered difficult. Endoscopists and pathologists should know the clinicopathological features of this highly malignant type of cancer.

Clinicopathological features, diagnosis, and treatment of sessile serrated adenoma/polyp with dysplasia/carcinoma

Sessile serrated adenoma/polyps (SSA/Ps) are early precursor lesions in the serrated neoplasia pathway, which results in BRAF-mutated colorectal carcinomas with not only high levels of microsatellite instability but also microsatellite stable. SSA/Ps with advanced histology, including cytological dysplasia or minimally invasive carcinomas, are important lesions because SSA/Ps are considered major contributors to "interval cancers" and these lesions can rapidly become dysplastic or invasive carcinomas. Clinicopathologically, SSA/Ps with dysplasia or invasive carcinoma were associated with advanced age, female sex, and proximal colon. Although SSA/Ps with submucosal invasive carcinoma were smaller and invaded less deeply into the submucosal layer than conventional tubular adenomas with submucosal invasive carcinoma, SSA/Ps with submucosal invasive carcinoma frequently had a mucinous component and exhibited a higher potential for lymphatic invasion and lymph node metastasis. In an SSA/P series, endoscopic characteristics, including (semi)pedunculated morphology, double elevation, central depression, and reddishness, may help accurately diagnose SSA/Ps with advanced histology. Removal of SSA/Ps with dysplasia or invasive carcinoma was recommended. Endoscopic treatment such as endoscopic mucosal resection or endoscopic submucosal dissection is useful for those lesions. However, surgical resection with lymph node dissection might be indicated when SSA/Ps with invasive carcinoma are endoscopically suspected, because these have the high risk of lymph node metastasis. Greater awareness may promote further research into improving the detection, recognition, and complete resection rates of SSA/Ps with dysplasia or invasive carcinoma and reduce the interval cancer rates.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Endoscopic diagnosis of sessile serrated adenoma/polyp with and without dysplasia/carcinoma

Sessile serrated adenoma/polyps (SSA/Ps) are early precursor lesions in the serrated neoplasia pathway, which results in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potentials. Detecting serrated lesions, including SSA/Ps with and without dysplasia/carcinoma, is critical, but SSA/Ps can be difficult to detect, are inconsistently identified by endoscopists and pathologists, and are often incompletely resected. Therefore, SSA/Ps are considered to be major contributors to “interval cancers”. If colonoscopists can identify the specific endoscopic characteristics of SSA/Ps, their detection and the effectiveness of colonoscopy may improve. Here, the endoscopic features of SSA/Ps with and without dysplasia/carcinoma, including the characteristics determined using magnifying endoscopy, are reviewed in the context of previous reports. Endoscopically, these subtle polyps are like hyperplastic polyps, because they are slightly elevated and pale. Unlike hyperplastic polyps, SSA/Ps are usually larger than 5 mm, frequently covered by a thin layer called the ‘‘mucus cap’’, and are more commonly located in the proximal colon. Magnifying narrow-band imaging findings, which include dark spots inside the crypts and varicose microvascular vessels, in addition to the type II-open pit patterns detected using magnifying chromoendoscopy, effectively differentiate SSA/Ps from hyperplastic polyps. The lesions’ endoscopic characteristics, which include their (semi)pedunculated morphologies, double elevations, central depressions, and reddishness, and the use of magnifying endoscopy, might help to detect dysplasia/carcinoma within SSA/Ps. Greater awareness may promote further research into improving the detection, identification, and complete resection rates of SSA/Ps with and without dysplasia/carcinoma and reduce the interval cancer rates.

Molecular and clinicopathological features of colorectal adenocarcinoma with enteroblastic differentiation

BACKGROUND

Colorectal adenocarcinoma with enteroblastic differentiation (CAED) is a rare subtype of colorectal malignancy with expression of enteroblastic markers (glypican 3, SALL4, AFP); however, the clinicopathological and epidemiological features are not fully elucidated.

AIMS

The aims of this study were to elucidate and establish the molecular and clinicopathological characteristics of CAED.

MATERIALS AND METHODS

In addition to three cases recently diagnosed as CAED, colorectal carcinoma (CRC) with expression of enteroblastic markers were selected by using immunohistochemistry (IHC) on tissue microarrays of 988 advanced CRC. We employed next-generation sequencing (NGS) and Sanger sequencing for the detection of genetic alterations. IHC for p53 and HER2, HER2-FISH and MSI status was also investigated. Survival analyses for clinicopathological parameters were performed using Kaplan-Meier methods.

RESULTS

Thirty-nine cases (4.0%) were positive for at least one enteroblastic marker. Histological evaluation of the total of 42 cases revealed that 10 contained tumour cells with clear cytoplasm. Enteroblastic marker-positive cases had aggressive behaviour and poor prognosis. NGS revealed TP53 as the most frequently mutated gene. The rate of HER2-positive cases and MSI-H cases was 9.5% (four of 42) and 12.2% (five of 41), respectively. Among these 42 cases, there were no molecular and clinicopathological differences according to the presence of tumour cells with clear cytoplasm.

CONCLUSIONS

Enteroblastic marker-positive CRC could be grouped together as CAED regardless of clear cell cytoplasm. Using this definition, the frequency of CAED is 4.0% and has a poorer prognosis than that for conventional CRCs. HER2 targeted therapy would be a meaningful treatment for CAED, and CAEDs contain both MSI-H and MSI-stable CRCs, although the MSS phenotype is dominant.

Mutation spectrum in the Wnt/β-catenin signaling pathway in gastric fundic gland-associated neoplasms/polyps

Frequent activation of the Wnt/β-catenin signaling pathway has recently been demonstrated in gastric adenocarcinoma/neoplasia of chief cell predominant type (GA-CCP/GN-CCP) with submucosal involvement. In this study, we examined the activation status of the Wnt/β-catenin signaling pathway in GN-CCP without submucosal involvement, which is referred to as gastric dysplasia-CCP (GD-CCP). We also examined β-catenin expression and the mutation spectrum of PPP2R1A and Wnt pathway genes in 11 cases of GD-CCP, 25 cases of gastric polyps of fundic gland type (GPs-FG), and 21 cases of GPs-FG with dysplasia (GP-FGD). β-catenin nuclear staining was observed in 3 cases of GD-CCP, none of GPs-FG, and 6 cases of GPs-FGD. Mutations in Wnt pathway genes, including PPP2R1A, were observed in 4 cases of GDs-CCP, 10 cases of GPs-FG, and 7 cases of GPs-FGD. Two of these seven GPs-FGD cases showed β-catenin nuclear staining. However, none of the 4 GD-CCP cases with mutations or the 10 GPs-FG cases with mutations showed β-catenin nuclear staining. PPP2R1A mutations were observed in 1 GD-CCP case and 1 GPs-FGD case. Although the mutation spectra of the Wnt pathway genes in GD-CCP and GP-FG differed, based on the absence of β-catenin nuclear staining despite the genetic alterations, GD-CCP is more similar to GP-FG than to GN-CCP, which shows β-catenin nuclear staining and submucosal involvement. Activation of the Wnt/β-catenin signaling by the β-catenin nuclear transition may be required during progression from GD-CCP to GN-CCP. Furthermore, this is the first report describing PPP2R1A mutations in gastric fundic gland-associated neoplasms.

TP53 inactivation and expression of methylation-associated proteins in gastric adenocarcinoma with enteroblastic differentiation

Gastric adenocarcinoma with enteroblastic differentiation (GAED) is a rare variant of aggressive adenocarcinoma. We demonstrated previously that GAED is genetically characterized by frequent TP53 mutation. In this study, we aimed to further clarify the mechanism of inactivation of TP53 in GAED in the light of promoter methylation of TP53, and expression of methylation-associated proteins such as Ten-eleven translocation (TET) 1 and 5-hydroxymethylcytosine (5-hmc) in addition to ATM mutations. We analyzed 51 cases of GAED. The ATM mutation was detected in only one case. Promoter methylation of TP53 was detected in 18% and frequency of loss of heterozygosity (LOH) at TP53 locus was 37.2%. Reduced TET1 expression was found in 29 cases (56.9%) and was significantly associated with advanced stage (p = 0.01), lymph node metastasis (p = 0.04), and macroscopic type (p = 0.01). Reduced 5-hmc expression was found in 28 cases (54.9%) and was significantly associated with advanced stage (p = 0.01), gender (p = 0.01), tumor location (p = 0.03), tumor size (p = 0.01), and lymph node metastasis (p = 0.01). Among 9 cases with TP53 promoter methylation, reduced expression of TET1 was observed in 6 cases, and reduced expression of 5-hmc was observed in 5 cases. Reduced expression of both TET1 and 5-hmc was significantly associated with adverse clinical outcomes. In summary, promoter methylation of TP53 is partly involved in loss of p53 expression. Aberrant methylation by reduced TET1 and 5-hmc may be involved in the development of aggressive GAED.

Continuation of antithrombotic therapy may be associated with a high incidence of colonic post-polypectomy bleeding

BACKGROUND AND AIM

Post-polypectomy bleeding (PPB) is the most common complication of endoscopic procedures. To reduce the risk of thromboembolic incidents, Japanese guidelines for gastroenterological endoscopy were revised to indicate that antithrombotic agents were not to be discontinued for endoscopic treatment. However, carrying out endoscopic procedures under antithrombotic medication potentially increases the incidence of hemorrhagic complications. The present study investigated the impact of the revised guidelines on the frequency of complications after colonoscopic procedures.

METHODS

The surveillance period comprised the year before the initiation of the new guidelines (2012), which served as a control period, and 2 years after initiation of the new guidelines (2013 and 2014). During the control period, 3955 cases were examined colonoscopically and 1601 lesions were treated endoscopically. During the 2-year period under the new guidelines, 8749 colonoscopies and 3768 endoscopic treatments were carried out. Changes in treatment methods and rates of complications were compared.

RESULTS

PPB rate was not significantly different before and after the revision (0.87% vs 1.01%). With the new guidelines, PPB rates in antithrombotic non-users and users were 0.60% and 3.13%, respectively (OR 5.11, P = 0.000). Multivariable analysis showed that the risks for PPB were as follows: heparin bridging therapy (OR 6.34, P = 0.0002); low-dose aspirin (LDA) continuation (OR 5.30, P = 0.0079); and lesion size (OR 1.06, P < 0.0001).

CONCLUSION

The present study showed that the overall PPB rate under the new guidelines was not significantly higher when compared with the previous data obtained before the new guidelines were introduced.

Distinct Involvement of the Sonic Hedgehog Signaling Pathway in Gastric Adenocarcinoma of Fundic Gland Type and Conventional Gastric Adenocarcinoma

BACKGROUND/AIMS

Gastric adenocarcinoma of fundic gland type (GAFG), which is a rare variant of gastric cancer, is reportedly associated with both Wnt/β-catenin signaling activation and guanine nucleotide binding protein, alpha stimulating complex (GNAS) mutations. This study aimed to elucidate potential roles of the Sonic hedgehog (Shh) signaling pathway in GAFG.

METHODS

We performed immunostaining for β-catenin and Shh signal-associated proteins, including Patched (Ptch), Smoothened (Smo), and Glioma-associated oncogene-1 (Gli1), and the direct sequencing of GNAS/BRAF/KRAS in 27 GAFGs, and compared them with 30 conventional gastric adenocarcinomas (CGAs).

RESULTS

GAFGs exhibited significantly lower immunoreactivity scores for Ptch, Smo, and Gli1 than CGAs. Moreover, while the Ptch score was significantly lower in the GAFG tumor areas than in the non-neoplastic areas adjacent to GAFG, the score was significantly higher in the CGA tumor areas than in the non-neoplastic areas. Similar trends were observed in the scores for Smo and Gli1. β-Catenin expression and GNAS mutations were found in 22 (81%) and 8 (30%) of the 27 GAFGs respectively. Gli1 expression was significantly associated with mutations in GNAS.

CONCLUSION

GAFG and CGA exhibited distinct Ptch, Smo, and Gli1 expression patterns. Downregulation of the Shh signaling pathway, as well as activation of the Wnt/β-catenin signaling pathway, may therefore be associated with tumorigenesis in GAFG.

Endoscopic Submucosal Dissection Decreases Additional Colorectal Resection for T1 Colorectal Cancer

Background

There are 3 methods of treating T1 colorectal cancer (T1 CRC), which include endoscopic resection, endoscopic resection followed by additional colorectal resection, and surgical resection. In this retrospective study, changes in the management of T1 CRC after introduction of endoscopic submucosal dissection (ESD) were investigated by comparison with the 10-year period before introduction of ESD.

Material/Methods

During a 20-year period from 1996 to 2015, 835 patients with T1 CRC were treated, including 331 patients before introduction of ESD (Group A) and 504 patients after introduction of ESD (Group B). Clinicopathological findings and treatment methods were compared between these 2 groups.

Results

As the initial treatment, endoscopic treatment was performed in 185 patients (55.9%) in Group A and 288 (57.1%) in Group B. In Group B, ESD was performed in 161 patients (55.9%), accounting for more than half of the T1 CRC patients receiving endoscopic treatment. In Groups A and B, observation after endoscopic resection was selected for 54.2% and 67.3% of T1a patients, respectively (p=0.04). A similar trend was noted for T1b patients, and there was no significant difference of the treatment approach. Among all T1 CRC patients, the percentage undergoing observation after endoscopic resection was significantly higher in Group B than in Group A (34.3% vs. 26.9%, p=0.02), and the percentage of patients undergoing additional colorectal resection was significantly lower in Group B (22.8% vs. 29.0%, p=0.04).

Conclusions

After introduction of ESD, it was performed in more than half of all patients with T1 CRC undergoing endoscopic treatment. The percentage of patients undergoing observation following endoscopic resection of T1 CRC increased after introduction of ESD.

Distinct histopathological characteristics in colorectal submucosal invasive carcinoma arising in sessile serrated adenoma/polyp and conventional tubular adenoma

The histopathological characteristics of colorectal submucosal invasive carcinoma arising in sessile serrated adenoma/polyp (SSA/P), a rare malignant tumour, have not yet been fully elucidated. To investigate the features of such, we retrospectively analysed 40 submucosal invasive carcinomas with SSA/P (CA-SSA/P) and compared them to 129 cases of submucosal invasive carcinoma with conventional tubular adenoma (CA-AD). We additionally performed hMLH1 immunostaining. CA-SSA/Ps were significantly smaller than CA-ADs (P < 0.001). Histologically, well to moderately differentiated adenocarcinoma was predominant in both CA-SSA/Ps and CA-ADs. No significant differences in depth of invasion were found between the two groups. However, lymphatic invasion was more often found in CA-SSA/Ps (30%) than in CA-ADs (13%; P = 0.028), as was lymph node metastasis (CA-SSA/Ps, 28%; CA-ADs, 7%; P = 0.011). Furthermore, mucinous component and serrated architecture were significantly more frequent in CA-SSA/Ps (30 and 63%) than in CA-ADs (5 and 18%; P < 0.001, respectively). Tumour-infiltrating lymphocytes and Crohn-like inflammatory reaction were also more frequently found in CA-SSA/Ps (70 and 30%) than in CA-ADs (31 and 9%; P ≤ 0.001, respectively), whereas the opposite was true of desmoplastic reaction (CA-SSA/Ps, 35%; CA-ADs, 67%; P < 0.001). Loss of hMLH1 expression was more frequent in CA-SSA/P cases (93%) than in CA-AD cases (5%; P < 0.001). In conclusion, CA-SSA/P lesions exhibit a higher potential for lymphatic invasion and lymph node metastasis and have distinct histopathological features, including mucinous component, serrated architecture, tumour-infiltrating lymphocytes, Crohn-like inflammatory reaction, and absence of desmoplastic reaction, compared to their conventional counterparts.

Epigenetic regulation of Wnt/β-catenin signal-associated genes in gastric neoplasia of the fundic gland (chief cell-predominant) type

Gastric neoplasia of the fundic gland (chief cell-predominant) type (GNCCP) is a rare variant of gastric tumor. This tumor is associated with activation of the Wnt/β-catenin signaling pathway; however, the mechanisms underlying this activation remain unknown. To elucidate potential roles of Wnt/β-catenin signal-associated gene methylation in GNCCP, we performed β-catenin immunostaining and methylation-specific polymerase chain reaction (PCR) for their associated genes, including SFRPs, APC, AXIN2, and MCC, in 26 GNCCPs [i.e., 11 intramucosal (GNCCP-Ms) and 15 submucosal tumors (GNCCP-SMs)], and compared with 27 fundic gland polyps (FGPs), 12 FGPs with dysplasia (FGP-Ds), 27 conventional gastric adenocarcinomas (CGAs). Nuclear β-catenin labeling indices were higher in GNCCPs and CGAs than in FGPs and FGP-Ds. SFRPs, APC, and AXIN2 were more frequently methylated in GNCCPs and CGAs (SFRP1, 88%/96%; SFRP2, 85%/93%; SFRP4, 73%/81%; APC, 81%/81%; AXIN2, 81%/85%; respectively) than in FGPs and FGP-Ds (37%/50%; 41%/42%; 41%/58%; 37%/33%; 41%/50%; respectively). A significant correlation was seen between nuclear β-catenin expression and methylation of SFRP1 in GNCCPs. Furthermore, nuclear β-catenin expression was significantly frequent in high-methylated GNCCPs than in low-methylated tumors. In conclusion, our results suggest that activation of this pathway, mediated by gene methylation, may be associated with progression of some GNCCP cases, similar to CGAs.

Frequent loss of heterozygosity of SMAD4 locus and prognostic impacts of SMAD4 immunohistochemistry in gastric adenocarcinoma with enteroblastic differentiation

Gastric adenocarcinoma with enteroblastic differentiation (GAED) is a rare variant of gastric adenocarcinoma. Clinicopathologically, GAED is known to be aggressive and is characterized by frequent vascular invasion, lymphatic invasion, and liver metastasis even in early stages. SMAD4 was identified as a frequently deleted gene in GAED by copy number variation analysis in our previous next-generation sequencing study; therefore, we examined the clinicopathological impacts of SMAD4 in 51 cases of GAEDs (early: 17, advanced: 34). We performed Sanger sequencing for SMAD4 mutations and loss of heterozygosity (LOH) analysis of the SMAD4 locus, in addition to immunohistochemistry for SMAD4, to determine its clinicopathological correlations and impacts on survival. The frequency of LOH at the SMAD4 locus was 45.1%, and it was significantly higher in GAED compared to in conventional gastric adenocarcinoma. SMAD4 mutations were not found in any case. Reduced SMAD4 expression was found in 60.8% of cases; it was significantly correlated with advanced stages and lymph node metastasis and showed trends of larger tumor size and lymphatic invasion. Reduced SMAD4 expression in metastatic lymph nodes was found in 21 of 36 cases. Survival analysis revealed that reduced SMAD4 expression significantly affected the patient's overall survival (OS) and recurrence-free survival (RFS), although multivariate analysis showed that only liver metastasis and lymphatic infiltration (Ly+) were independent prognostic factors for OS and RFS. The SMAD4 locus is one of the susceptibility genes in this tumor, although SMAD4 mutation was not detected. Furthermore, the inactivation of SMAD4 appeared to contribute to the aggressiveness of GAED.

Early Clinical Remission Is a Predictor of Long-Term Remission with the Use of Vedolizumab for Ulcerative Colitis

Vedolizumab (VDZ) is an α4β7 integrin-antibody used to manage refractory ulcerative colitis (UC). This retrospective multicenter study aimed to identify predictors of efficacy or the time points when evaluation of VDZ therapy for UC would be most useful. We compiled data on 87 patients with moderate to severe active UC that was treated with VDZ. Overall clinical remission (CR) rates at 6 weeks and 52 weeks after VDZ administration were 44.4% (bio-naïve 44.2%, bio-failure 44.8%) and 52.8% (bio-naïve 53.5%, bio-failure 51.7%) respectively. Also, 83.3% (bio-naïve 81.3%, bio-failure 85.7%) of patients achieved mucosal healing at week 52. Among patients with a CR at week 52, 73.3% had a CR at week 6. In contrast, of patients who discontinued VDZ, 82.4% had not reached a CR at week 6. Our study demonstrated that VDZ was effective in a large percentage of UC patients, with a high mucosal healing rate even after prior biological exposures. This suggests that VDZ can be a treatment option even in bio-failure cases. Additionally, it was considered that early CR can predict long-term remission and that week 6 can be a helpful evaluation point for treatment decisions when using VDZ for UC.

Linked color imaging improves visibility of colorectal serrated lesion by high color contrast to surrounding mucosa

OBJECTIVES

This study aimed to objectively evaluate the efficacy of linked color imaging (LCI) in diagnosing colorectal serrated lesions by utilizing visibility scores and color differences.

METHODS

We examined 89 serrated lesions, including 36 hyperplastic polyps (HPs), 47 sessile serrated lesions (SSLs), and six traditional serrated adenomas (TSAs). Visibility changes were scored by six endoscopists as follows: 4, excellent; 3, good; 2, fair; and 1, poor. Furthermore, images obtained by white-light imaging (WLI) or LCI were assessed using the CIELAB color space in the lesion and adjacent mucosa. We calculated the mean color values (L*, a*, and b*) measured at five regions of interest of the sample lesion and surrounding mucosa and derived the color difference (ΔE*).

RESULTS

The visibility scores of both HPs and SSLs in LCI were significantly higher than that in WLI (HPs, 3.67/2.89, P < 0.001; SSLs, 3.07/2.36, P < 0.001). Furthermore, SSLs showed a significantly higher L* value and significantly lower a* and b* values in LCI than the adjacent mucosae (L*, 61.76/58.23, P = 0.016; a*, 14.91/17.58, P = 0.019; b*, 20.42/24.21, P = 0.007), while WLI produced no significant difference in any color value. A similar trend was apparent in HPs. In all serrated groups, LCI revealed significantly greater ΔE* values between the lesion and adjacent mucosa than WLI (HPs, 11.54/6.12; SSLs, 13.43/7.67; TSAs, 35.00/22.48).

CONCLUSION

Linked color imaging showed higher color contrast between serrated lesions and the surrounding mucosae compared with WLI, indicating improved visibility of colorectal serrated lesion using LCI.

Efficacy and Acceptability of 1 Liter of Polyethylene Glycol with Ascorbic Acid vs. 2 Liters of Polyethylene Glycol Plus Mosapride and Sennoside for Colonoscopy Preparation

BACKGROUND [color=black]Bowel preparation is an important factor for an optimal outcome of colonoscopy. Recently, polyethylene glycol (PEG) solution has been in common use for bowel cleansing for colonoscopy, but some patients are intolerant of PEG because of taste or volume. A low-volume PEG administered with ascorbic acid solution (PEG-Asc) was designed to improve tolerability, but the administration of this method is more complex than that with PEG alone. This study aimed to compare bowel cleansing efficacy, safety, and tolerability of 1 L PEG-Asc with a 2 L PEG preparation with use of sennosides and mosapride.[/color] MATERIAL AND METHODS [color=black]This was a prospective, single-center, non-inferiority trial that included 112 patients (PEG-Asc group, 68; PEG group, 44). The primary endpoint was the efficacy of colon cleansing assessed by endoscopists using a validated 4-point scale according to the Aronchick scale and was verified by a blinded investigator. Acceptability, tolerability, and adenoma detection rate (ADR) of these 2 regimens were secondary endpoints.[/color][color=black] [/color] RESULTS [color=black]We found no statistically significant differences between the groups in colon-cleansing efficacy or in the adenoma detection rate (ADR). Moreover, overall, patients significantly favored PEG-Asc over PEG, reflecting better acceptance of PEG-Asc. Additionally, more patients favored PEG-Asc over PEG for a hypothetical future colonoscopy. [/color] CONCLUSIONS [color=black]The alternate 1 L PEG-Asc regimen and standard 2 L PEG regimen were clinically equivalent with respect to cleansing efficacy, safety, and ADR, and more patients favored PEG-Asc than PEG. This alternate regimen may improve patient compliance and acceptance of surveillance colonoscopy.[/color].

Pyoderma gangrenosum in an ulcerative colitis patient during treatment with vedolizumab responded favorably to adsorptive granulocyte and monocyte apheresis

Pyoderma gangrenosum (PG) is an extra-intestinal skin lesion in inflammatory bowel disease (IBD) as is erythema nodosum. Vedolizumab (VED) is a monoclonal antibody that targets α4β7 integrin and has an intestinal selective mechanism. Despite good therapeutic effects on colitis, the effect on extra-intestinal manifestations (EIMs) remains unclear. Here we report a case of ulcerative colitis complicated by PG during treatment with VED, which was successfully treated with prednisolone in combination with adsorptive granulocyte and monocyte apheresis (GMA). The patient was a 50-year-old woman with a past medical history of extensive ulcerative colitis managed by golimumab (GLM). She developed flare symptoms due to loss of response to GLM, and treatment was switched to VED. Her gastrointestinal symptoms were improved with VED treatment with less frequent bowel movements. However, infiltrative erythema with pain appeared on the right lower leg and right knee, and expanded and gradually ulcerated. Her skin lesions were treated with corticosteroid, but showed poor improvement. Therefore, granulocyte and monocyte apheresis (GMA) treatment was administered in combination with prednisolone. After 3 months, the ulcer gradually improved, and at the time of this writing, the eruptions were nearly replaced by epithelial tissue. This case study showed that patients with UC and EIMS may respond well to combination therapy of VED and GMA. GMA has a very favorable safety profile. On the other hand, the causal connection between VED and PG is still unclear. We believe that a combination therapy involving VED and GMA in IBD patients with EIMs warrants consideration.