The pathology of epithelial pre-malignancy of the gastrointestinal tract

Transgelin Inhibits the Malignant Progression of Esophageal Squamous Cell Carcinomas by Regulating Epithelial-Mesenchymal Transition

Objective

This article investigates the role of Transgelin (TAGLN) in the epithelial–mesenchymal transition (EMT) of esophageal squamous cell carcinomas (ESCC) and its possible mechanism of inhibiting the invasion of these cancers.

Methods

Tissue specimens and clinical information of patients with ESCC were collected to analyze the relationship between Transgelin expression level and prognosis of patients with ESCC. Transgelin siRNA was used to knock down Transgelin expression. The expression of Transgelin in Eca-109 and KYSE-150 cells was overexpressed by Transgelin-overexpressing plasmid. The effects of Transgelin overexpression and knockdown on the proliferation of Eca-109 and KYSE-150 cells were examined by Transwell chamber, scratch assay, and CCK-8 cell activity assay. RT-PCR and Western blot were used to detect the effect of Transgelin overexpression or knockdown on the mRNA and protein expressions of E-cadherin and Vimentin. TCGA data were used to analyze Transgelin co-expressed genes and further study the GO and KEGG enrichment analysis results under the influence of Transgelin.

Results

The expression of Transgelin was low in ESCC, and its expression level was positively correlated with the prognosis of patients with ESCC. The targeted Transgelin siRNA and Transgelin-overexpressing plasmid can effectively regulate the expression of Transgelin mRNA and protein in Eca-109 and KYSE-150 cells. After overexpression of Transgelin, the invasion and proliferation abilities of Eca-109 and KYSE-150 cells were significantly decreased compared with those of the control group (P < 0.05). However, Transgelin knockdown could promote the proliferation, migration, and invasion of ESCC cells. The overexpression of Transgelin inhibits EMT in ESCC. With the increase of Transgelin expression in Eca-109 and KYSE-150 cells, the expression of E-cadherin increased, while the expression of Vimentin decreased, and the difference was statistically significant (P < 0.05).

Conclusion

Transgelin can inhibit the malignant progression of ESCC by inhibiting the occurrence of EMT.

The evaluation of colon biopsies using virtual microscopy is reliable

AIMS

Virtual microscopy offers major advantages for pathology practice, separating slide evaluation from slide production. The aim of this study was to investigate the reliability of using whole slide images as compared with routine glass slides for diagnostic purposes.

METHODS AND RESULTS

Colon biopsies (n = 295) were assessed using both glass slides and whole slide images by four pathologists and two residents. Two pathologists scored the digital images of biopsies in a primary diagnostic setting. For each case, the consensus diagnosis was defined as the majority diagnosis on the study's glass slides. All diagnoses were grouped into seven main diagnostic categories, and further divided into subgroups. The overall concordance rates were 89.6% for whole slide images and 91.6% for light microscopy. The concordance rates of the subgroups 'adenoma' and 'adenocarcinoma' between whole slide images and conventional microscopy showed only small variability. The intraobserver (whole slide images versus glass slide) agreement, including subgroups, was substantial, with a mean κ-value of 0.78, and was higher than the interobserver agreement for glass slides (interobserver κ-value of 0.69).

CONCLUSIONS

This study shows good diagnostic accuracy and reproducibility for virtual microscopy, indicating that this technology can reliably be used for pathological evaluation of colon biopsies in a primary clinical setting.

Protein kinase Cbeta is an effective target for chemoprevention of colon cancer

Colon cancer develops over a period of 10 to 15 years, providing a window of opportunity for chemoprevention and early intervention. However, few molecular targets for effective colon cancer chemoprevention have been characterized and validated. Protein kinase CbetaII (PKCbetaII) plays a requisite role in the initiation of colon carcinogenesis in a preclinical mouse model by promoting proliferation and increased beta-catenin accumulation. In this study, we test the hypothesis that PKCbetaII is an effective target for colon cancer chemoprevention using enzastaurin (LY317615), a PKCbeta-selective inhibitor, in a mouse model of colon carcinogenesis. We find that enzastaurin potently reduces azoxymethane-induced colon tumor initiation and progression by inhibiting PKCbetaII-mediated tumor cell proliferation and beta-catenin accumulation. Biochemically, enzastaurin reduces expression of the PKCbetaII- and beta-catenin/T-cell factor-regulated genes PKCbetaII, cyclooxygenase II, and vascular endothelial growth factor, three genes implicated in colon carcinogenesis. Our results show that enzastaurin is an effective chemopreventive agent in a mouse model of sporadic colon cancer that significantly reduces both tumor initiation and progression by inhibiting expression of proproliferative genes. Thus, PKCbetaII is an important target for colon cancer chemoprevention and the PKCbeta-selective inhibitor enzastaurin may represent an effective chemopreventive agent in patients at high risk for colon cancer.

[Dysplasia in glandular digestive tissues: new concepts, new classifications]

The term of dysplasia is currently used to designate morphological alterations, identifiable at microscopic examination, revealing the existence of an unequivocally neoplastic process, at an early, non-invasive, stage of its natural history. The pathologist bears the full responsibility for the diagnosis of dysplasia, based on a broad spectrum of cytological and architectural abnormalities. It is important to grade the severity of the dysplastic lesions, in order to help guide clinical management and choose the therapeutic strategy. The Vienna classification, proposed in 2000 as a compromise between the Western and Japanese concepts, is now used for classification and grading of digestive epithelial dysplasia. The major advantages of the Vienna classification are the use of uniform terminology worldwide, achievement of good diagnostic reproducibility between pathologists and clear and consensual clinical consequences. Its use is strongly supported by the recent international recommendations.

Gastric adenomas: relationship between clinicopathological findings, Helicobacter pylori infection, APC mutations and COX-2 expression

Gastric adenomas are rare neoplastic growths characterized by localized polypoid proliferations of dysplastic epithelium that tend to progress to infiltrating adenocarcinoma. Therefore, the identification of molecular markers that could reliably recognize adenomas at risk of progression is advocated in the clinical management. In this study we investigated, in a series of gastric adenoma specimens from an area at high risk of gastric cancer, the relationship between clinicopathological characteristics of adenoma and Helicobacter pylori infection, APC mutational status, and COX-2 and the down-stream enzyme mPGES1 expression. Helicobacter pylori infection, detected in 24%, and 33% by histology and PCR analyses, respectively, did not show any relationship with growth pattern, localization, size, dysplasia grade and presence of synchronous cancer. Pathogenetic mutations of MCR region (codons 1269-1589) of the APC gene were detected only in one case corresponding to a single, small size, low grade, H. pylori-negative adenoma. The expression of COX-2 largely matched that of mPGES(1). Both were overexpressed in 79% of cases showing a relationship with high-grade dysplasia, size >10 mm and presence of a synchronous carcinoma. In conclusion, COX-2 may play a key role in the development and progression of gastric adenoma and could be an attractive target in the management of gastric adenoma at major risk of cancer development.

Dual infection with Helicobacter bilis and Helicobacter hepaticus in p-glycoprotein-deficient mdr1a-/- mice results in colitis that progresses to dysplasia

Patients with inflammatory bowel disease (IBD) are at increased risk for developing high-grade dysplasia and colorectal cancer. Animal IBD models that develop dysplasia and neoplasia may help elucidate the link between inflammation and colorectal cancer. Mdr1a-/- mice lack the membrane efflux pump p-glycoprotein and spontaneously develop IBD that can be modulated by infection with Helicobacter sp: H. bilis accelerates development of colitis while H. hepaticus delays disease. In this study, we determined if H. hepaticus infection could prevent H. bilis-induced colitis. Unexpectedly, a proportion of dual-infected mdr1a-/- mice showed IBD with foci of low- to high-grade dysplasia. A group of dual-infected mdr1a-/- animals were maintained long term (39 weeks) by intermittent feeding of medicated wafers to model chronic and relapsing disease. These mice showed a higher frequency of high-grade crypt dysplasia, including invasive adenocarcinoma, possibly because H. hepaticus, in delaying the development of colitis, allows time for transformation of epithelial cells. Colonic epithelial preparations from co-infected mice showed increased expression of c-myc (5- to 12-fold) and interleukin-1alpha/beta (600-fold) by real-time polymerase chain reaction relative to uninfected wild-type and mdr1a-/- animals. This animal model may have particular relevance to human IBD and colorectal cancer because certain human MDR1 polymorphisms have been linked to ulcerative colitis and increased risk for colorectal cancer.

A follow up model for patients with atrophic chronic gastritis and intestinal metaplasia

AIM

To devise a follow up model for patients with gastric cancer associated lesions, such as atrophic chronic gastritis (ACG) and intestinal metaplasia (IM).

METHODS

Cohort study of 144 patients, followed for a minimum of one year, in whom at least two upper gastrointestinal endoscopic biopsies in flat gastric mucosa provided a diagnosis of ACG, IM, or low grade dysplasia (LGD).

RESULTS

Of those diagnosed with ACG at first endoscopic biopsy (entry biopsy), 12% progressed to LGD in outcome biopsy, as did 8% of those with type I IM, 38% with type II or III IM, and 32% with LGD. Type of IM at entry independently predicted progression to LGD and cancer. Type II and III IM had a higher rate of progression to LGD than type I IM, which showed an indolent behaviour similar to ACG. Patients with type II or III IM were at higher risk for development of dysplasia, and 7% of patients with type III IM at first biopsy progressed to high grade dysplasia (HGD), whereas no cases of ACG or type I/II IM progressed to HGD during the first three years.

CONCLUSION

Patients with ACG or IM could possibly be allocated to different management schedules, based on differences in rate and proportion of progression to LGD or HGD. Less intensive follow up (two/three yearly with "serological evaluation" (pepsinogen)) may suit those with ACG or type I IM. Patients with type III IM may benefit from six to 12 monthly improved endoscopic examination (magnification chromoendoscopy).

Surveillance in Barrett's oesophagus: a critical reappraisal

BACKGROUND

Current recommendations are for endoscopic surveillance of patients with Barrett's oesophagus to detect dysplasia and to diagnose carcinoma at an early and possibly treatable stage. However, observations suggest that these current practice guidelines are thwarted by many factors often not taken into account. These observations stem from general surveillance aspects as well from specific data on Barrett's oesophagus. This review therefore aims at discussing data on the current surveillance strategy in conjunction with general surveillance aspects relevant for their interpretation.

METHODS

Literature survey of published articles.

RESULTS

A critical reappraisal of the literature shows that the current surveillance strategy is hampered by multiple problems with the marker dysplasia, cost-ineffectiveness, an overrated cancer risk and an astonishing lack of prospective, randomized data showing a clear benefit in terms of a greater life expectancy. Moreover, the decisive study is unlikely ever to be performed because of the large number of patients needed and the required length of follow-up. As a result, protocols are being carried out that have never been critically tested prior to large-scale clinical implementation.

CONCLUSIONS

Although these findings should not lead to therapeutic nihilism, the data raise the issue of whether or not surveillance protocols should be restricted to specialized referral centres with particular research efforts aimed at improving existing and developing new techniques that lack most of the described pitfalls and problems. Since it is foreseen that matters will not change rapidly in the (near) future, the clinician has no other choice than to rely on individually tailored arguments to survey taking into account for example family history, age and anxiety about potential long-term effects.

Symposium part 2: Should the Bethesda System terminology be used in diagnostic surgical pathology?: Counterpoint

The criteria currently used for grading cervical intraepithelial neoplasia (CIN) are arbitrary and subjective with consequent considerable intra- and interobserver variability. None of the currently used criteria make a clear-cut case for changing terminology. The combination of CIN 2 and CIN 3 into a high-grade lesion is not supported by biologic behavior or HPV typing and leads to overtreatment. The various shifts in nomenclature over the last 50 years through the dysplasia, CIN, and Bethesda systems, although intellectually stimulating, have neither improved diagnostic accuracy nor patient management. On the contrary, they often caused confusion and duplication, leading to the common and ironic practice that several terminologies are now being used in an additive fashion. New diagnostic markers are on the horizon as a result of the rapid development in the areas of genomics and proteomics. It seems likely that specific molecular biomarkers will become available, allowing the consistent and accurate discrimination between those intraepithelial lesions that will ultimately become invasive from the vast majority of lesions that will regress or persist. It is preferable at this time to maintain the current three-tier system, which is well entrenched and accepted around the world, until a novel approach places the classification of cervical precursor lesions on a new and solid footing. Ideally, we will then have a single-tier system identifying reliably those lesions that have the potential to become invasive.