SUMMARY BackgroundVonoprazan, a potassium-competitive acid blocker, is expected to improve the healing of endoscopic submucosal dissection (ESD)-induced gastric ulcers compared with proton pump inhibitors (PPIs).

NANOG protein, a transcription factor expressed in embryonic stem cells, is overexpressed in tumor development. Although studies investigating the function of NANOG in cancer have shown that it plays several roles, such as in cell proliferation, invasion and metastasis, the overall function of NANOG in cancer cells has remained elusive. In the present study, NANOG expression in oral squamous cell carcinoma (OSCC) was examined to determine its potential clinical significance. The expression of NANOG protein was assessed in 60 patients with OSCC by immunohistochemistry, and its correlation with clinicopathological factors and metastasis was evaluated. NANOG protein levels in human OSCC cell lines were determined by western blotting and immunofluorescence staining. NANOG protein expression was identified in 52 cases (86.7%) and expression levels were higher in primary foci of poorly differentiated OSCC than in those of well-differentiated OSCC, indicating that NANOG expression is associated with OSCC differentiation. Regardless of the differentiation levels of primary foci, NANOG expression levels in metastatic foci were extremely high. In addition, NANOG expression in metastatic foci was maintained at high levels following preoperative adjuvant therapy. Furthermore, NANOG protein was detected at an identical level in human OSCC cell lines. These data indicate that NANOG-expressing OSCC cells tend to metastasize and that metastatic tumors expressing NANOG may be resistant to preoperative adjuvant therapy, including chemoradiation. Thus, assessment of NANOG expression may assist the strategy for treatment of OSCC metastasis.

Background & Aims: Acute pancreatitis is a major adverse event of endoscopic retrograde cholangiopancreatography (ERCP). Rectal administration of non-steroidal anti-inflammatory drugs (NSAIDs) decreases the incidence of post-ERCP pancreatitis (PEP). Little is known about the combined effects of sublingual nitrate and NSAIDs. We performed a randomized trial to assess whether the combination of NSAIDs and sublingual nitrate is more effective than NSAIDs alone in preventing PEP. Methods: In a prospective superiority trial, eligible patients underwent ERCP at 12 endoscopic units in Japan, from March 2015 through May 2018. Patients were randomly assigned to groups given diclofenac suppositories (50 mg) within 15 minutes after the endoscopic procedure alone (diclofenac alone group, n=442) or in combination with sublingual isosorbide dinitrate (5 mg) 5 minutes before the endoscopic procedure (combination group, n=444). The primary endpoint was the occurrence of PEP. Results: Post-ERCP pancreatitis developed in 25 patients in the combination group (5.6%), and in 42 patients in the diclofenac alone group (9.5%) (relative risk, 0.59; 95% CI, 0.37-0.95; P=.03). Moderate to severe pancreatitis developed in 4 patients (0.9%) in 6 the combination group, and 10 patients (2.3%) in the diclofenac alone group (relative risk, 0.12; 95% CI, 0.13-1.26; P = 0.12). There was no serious adverse event related to the additional administration of sublingual nitrate. Conclusions: In a randomized controlled trial, we found that prophylaxis with rectal diclofenac and sublingual nitrate significantly reduces the overall incidence of PEP compared with diclofenac suppository alone. ClinicalTrials.gov, no: UMIN 000016274

Preoperative elevated serum CA19-9 and total bilirubin levels are prognostic factors for ampullary adenocarcinoma, and are both associated with pancreatobiliary-type tumors. Surgeons should be aware of these factors because pancreatobiliary-type adenocarcinoma is aggressively invasive and is associated with poor survival.

The epithelial lining of odontogenic keratocysts exhibits either parakeratosis or orthokeratosis. In 2005, the WHO classified odontogenic keratocysts with parakeratosis as keratocystic odontogenic tumors (KCOT). Odontogenic keratocysts with orthokeratosis were not classified as odontogenic tumors, but instead referred to as orthokeratinized odontogenic cysts (OOC). To clarify the difference between these two lesions, we investigated their biological characteristics using immunohistochemical studies for cytokeratins (CK) in KCOT and OOC as well as in dentigerous cysts (DC), radicular cysts (RC) and dermoid cysts (DMC). We examined twenty-five cases of KCOT, fifteen cases each of OOC, DC and RC, and ten cases of DMC. We studied the immunohistochemical expression of CK10, 13, 17 and 19. To evaluate the immunohistochemical staining pattern, we divided the epithelial lining of the lesions into three layers (surface layer: su, spinous layer: sp, basal layer: ba). For CK10, most OOC and DMC specimens of su and sp were positive. For CK13 and 19, most KCOT, DC and RC specimens of su and sp were positive. For CK17, most KCOT specimens of su and sp were positive. The percentages of total CK expression of su and sp, and ba of CK19 differed significantly between the lesions (P < 0.001). These results support the hypothesis that OOC originate from not the odontogenic apparatus, but the oral epithelial component.

Ameloblastoma (AB), which is the most common odontogenic tumor, may originate from the dental lamina remnants. The expression of CD56, which is a transmembrane molecule, is associated with neuroectodermal differentiation of the embryonal cells. The aim of this study was to evaluate the expression of CD56 in AB, in comparison with other odontogenic cysts. We used formalin-fixed, paraffi n-embedded specimens from 34 cases of AB, 10 cases of keratocystic odontogenic tumor (KCOT), and 7 cases of dentigerous cyst (DC). We immunohistochemically examined CD56, NeuroD1, and N-cadherin expression in these tumors as compared with the expression patterns of various epithelial markers. Seventy-four percent of AB showed immunopositivity for CD56, and both CD56 and N-cadherin were diffusely positive in the outer columnar cells of AB. The immunopositivities for NeuroD1 and N-cadherin were also observed in the outer cells of AB. None of the DC cases was positive for CD56, whereas half the cases of KCOT were positive. Because CD56 is expressed in the inner enamel epithelium of enamel organs, the outer columnar cells of AB are likely to be the differentiation phenotype of the inner enamel epithelium, which is associated with neuroectodermal differentiation. The aberrant NeuroD1 expression may induce CD56 expression in AB and KCOT.

These results indicate that lymphatic proliferation might be much more extensive in the peritumoral area than intratumoral.

Epithelial mesenchymal transition (EMT), the transition of epithelial cells into motile mesenchymal cells, plays an important role in embryogenesis, cancer invasion, and metastasis. Ameloblastomas are common epithelial odontogenic tumors, occurring exclusively in the mandible with locally invasive growth. Thirty-seven ameloblastoma cases were evaluated for the involvement of EMT by immunohistochemical staining and western blotting using antibodies against Slug, Snail, Twist, TGF-β, and E-cadherin. Double immunostaining was also performed. Slug and TGF-β were expressed in the nuclei of peripheral and stellate reticulum cells of ameloblastoma nests. Twenty cases of Snail, 36 of Slug, 8 of Twist, and 19 of TGF-β showed strong expression in tumor cells in follicular and plexiform patterns. Expression of Slug and TGF-β increased in regions where the expression of E-cadherin was reduced. EMT was found to be associated with the local invasive growth of ameloblastoma. These data suggest that reduced expression of E-cadherin and over-expression of Slug, Snail, and TGF-β induce EMT. Given that ameloblastomas are characterized by local invasiveness, EMT might be related to their development. Thus, strong expression of Slug and TGF-β and reduced expression of E-cadherin might be related to the local invasiveness of ameloblastoma.