Differences in biological features of gastric dysplasia, indefinite dysplasia, reactive hyperplasia and discriminant analysis of these lesions

Unique immunohistochemical profiles of MUC5AC, MUC6, P53, and Ki67 in gastric atypical hyperplasia and dysplasia

OBJECTIVES

Differentiating gastric atypical hyperplasia (AH) from dysplasia, including low-grade dysplasia (LGD) and high-grade dysplasia (HGD), poses significant challenges in small biopsies and specimens with technical artifacts. This study aims to establish objective diagnostic criteria for these conditions through combined morphologic and immunohistochemical (IHC) analyses.

METHODS

Between January 2018 and September 2020, a total of 123 gastric mucosa biopsy specimens were collected at Anyang Tumor Hospital. According to the WHO Classification of Digestive System Tumors (5th edition), specimens were categorized into three groups: AH (n=48), LGD (n=30), and HGD (n=45). Morphologic characteristics were assessed, and IHC staining for MUC5AC, MUC6, MUC2, CD10, P53, and Ki67 was performed, followed by statistical analysis.

RESULTS

Histologically, AH was predominantly marked by a pronounced inflammatory background (60.42%), intestinal metaplasia (64.58%), indistinct boundaries (83.33%), and a distinct maturation gradient (97.72%). AH nuclei were typically circular (97.92%), with a high nucleus-to-cytoplasm ratio (64.58%), prominent nucleoli (47.92%), and preserved polarity (89.58%). In contrast, LGD and HGD typically exhibited well-defined boundaries with an absent maturation gradient. LGD nuclei were rod-shaped (96.67%), with a low nucleus-to-cytoplasm ratio (96.67%) and preserved polarity (100%), whereas HGD demonstrated a loss of cellular polarity (77.78%). IHC findings revealed a consistent maturation gradient in AH, with polarized MUC5AC and MUC6 expression, significantly reduced in LGD (86.67%), and absent in HGD. P53 expression in HGD showed a predominant 'mutation-type pattern' (66.67%), contrasting with 'wild-type pattern' expression in AH and LGD (100%, 93.33%). Ki67 expression patterns varied from a 'pit neck pattern' in AH (95.83%) to a 'polarity pattern' in LGD (76.67%) and a 'diffuse pattern' in HGD (57.78%). The expression patterns of MUC5AC, MUC6, CD10, P53, and Ki67 varied significantly across the three groups (P<0.001).

CONCLUSIONS

The integration of histomorphological features and expression profiles of MUC5AC, MUC6, P53, and Ki67 is instrumental in diagnosing gastric atypical hyperplasia and dysplasia.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.

Chinese integrated guideline on the management of gastric precancerous conditions and lesions

The standardized diagnosis and management of gastric precancerous conditions and lesions are important to prevent gastric cancer. This guideline, created by 5 traditional Chinese medicine and Western medicine associations, based on the current morbidity and diagnosis and treatment of gastric precancerous conditions and lesions, provides specific key points and strategies for diagnosis and treatment in the following five aspects: definition and epidemiology, diagnosis and stage, surveillance, treatment and efficacy evaluation. It is hoped that these aspects, assessed by integrating Western medicine and traditional Chinese medicine and involving multidisciplinary participation, will play a guiding role in clinical diagnosis and treatment and achieve effective secondary prevention of gastric cancer.

The application of transgenic and gene knockout mice in the study of gastric precancerous lesions

Gastric intestinal metaplasia is a precursor for gastric dysplasia, which is in turn, a risk factor for gastric adenocarcinoma. Gastric metaplasia and dysplasia are known as gastric precancerous lesions (GPLs), which are essential stages in the progression from normal gastric mucosa to gastric cancer (GC) or gastric adenocarcinoma. Genetically-engineered mice have become essential tools in various aspects of GC research, including mechanistic studies and drug discovery. Studies in mouse models have contributed significantly to our understanding of the pathogenesis and molecular mechanisms underlying GPLs and GC. With the development and improvement of gene transfer technology, investigators have created a variety of transgenic and gene knockout mouse models for GPLs, such as H/K-ATPase transgenic and knockout mutant mice and gastrin gene knockout mice. Combined with Helicobacter infection, and treatment with chemical carcinogens, these mice develop GPLs or GC and thus provide models for studying the molecular biology of GC, which may lead to the discovery and development of novel drugs. In this review, we discuss recent progress in the use of genetically-engineered mouse models for GPL research, with particular emphasis on the importance of examining the gastric mucosa at the histological level to investigate morphological changes of GPL and GC and associated protein and gene expression.

Use of DNA flow cytometry in the diagnosis, risk stratification, and management of gastric epithelial dysplasia

The natural history of gastric epithelial dysplasia and the consequential surveillance strategies are not well defined in the West. To date, the diagnosis relies on morphology, and no reliable adjunct methods, either immunohistochemical or molecular, have reproducibly been able to confirm the diagnosis and/or risk stratify gastric epithelial dysplasia. Yet, such a tool would be useful in confirming the diagnosis, and developing objective and rational surveillance guidelines. DNA flow cytometry was performed using formalin-fixed paraffin-embedded gastric tissue from 23 cases of high-grade dysplasia and 38 cases of low-grade dysplasia. Twenty-four benign background mucosal samples from the same cohort (20 biopsies and 4 surgical resections from 16 low- and 8 high-grade dysplasia cases) were utilized as controls. The presence of DNA content abnormality (aneuploidy or elevated 4N fraction) correlated with increasing levels of dysplasia, as DNA content abnormality was detected in 18 (78%) of 23 high-grade dysplasia, 5 (13%) of 38 low-grade dysplasia, and none of 24 non-dysplastic samples. 1 and 4-year detection rates of high-grade dysplasia or gastric adenocarcinoma in low-grade dysplasia patients with DNA content abnormality were 80% (p = 0.003) and 100% (p = 0.005), respectively, whereas patients with low-grade dysplasia but with normal DNA content had 1, 4, and 12-year detection rates of 23, 32, and 54%, respectively. The univariate hazard ratio (HR) for subsequent detection of high-grade dysplasia or gastric adenocarcinoma in low-grade dysplasia patients with DNA content abnormality was 6.9 (p = 0.001). Older patients (HR = 1.1, p = 0.005) and those with familial adenomatous polyposis (HR = 9.7, p = 0.029) also had an increased risk for developing high-grade dysplasia or gastric adenocarcinoma in the univariate analysis, but only DNA content abnormality demonstrated a significantly elevated HR of 5.9 in the multivariate analysis (p = 0.005). While older age showed a minimally elevated risk (HR = 1.1, p = 0.013), no other potential risk factors, including male gender, ethnicity, polypoid endoscopic appearance, Helicobacter pylori infection, and intestinal metaplasia, were significantly associated with subsequent detection of high-grade dysplasia or gastric adenocarcinoma in the multivariate analysis. Among the 18 high-grade dysplasia cases with DNA content abnormality, 13 cases (72%) developed gastric adenocarcinoma within a mean follow-up time of 9 months, conferring a HR of 2.5; however, this did not reach statistical significance. In conclusion, the presence of DNA content abnormality can identify a subset of low-grade dysplasia patients who are at increased risk for subsequent detection of high-grade dysplasia or gastric adenocarcinoma. It can also provide confirmatory evidence to a morphologic impression or suspicion of high-grade dysplasia. The majority of gastric epithelial dysplasia patients with DNA content abnormality developed high-grade dysplasia or gastric adenocarcinoma within a year and thus may benefit from more thorough and rigorous endoscopic surveillance.

Gastric Cancer as Preventable Disease

Gastric cancer, 1 of the 5 most common causes of cancer death, is associated with a 5-year overall survival rate less than 30%. A minority of cancers occurs as part of syndromic diseases; more than 90% of adenocarcinomas are considered as the ultimate consequence of a longstanding mucosal inflammation. Helicobacter pylori infection is the leading etiology of non-self-limiting gastritis, which may result in atrophy of the gastric mucosa and impaired acid secretion. Gastric atrophy establishes a field of cancerization prone to further molecular and phenotypic changes, possibly resulting in cancer growth. This well-understood natural history provides the clinicopathologic rationale for primary and secondary cancer prevention strategies. A large body of evidence demonstrates that combined primary (H pylori eradication) and secondary (mainly endoscopy) prevention efforts may prevent or limit the progression of gastric oncogenesis. This approach, which is tailored to different country-specific gastric cancer incidence, socioeconomic, and cultural factors, requires that the complementary competences of gastroenterologists, oncologists, and pathologists be amalgamated into a common strategy of health policy.

Establishment of a combination scoring method for diagnosis of ocular adnexal lymphoproliferative disease

Lymphoproliferative diseases (LPDs) of the ocular adnexa encompass the majority of orbital diseases and include reactive follicular hyperplasia (RFH), atypical lymphoid hyperplasia (ALH), and mucosa-associated lymphoid tissue lymphoma (MALToma). Lymphoid follicles (LFs) are usually observed during the histological examination of LPDs. Currently, because there is a lack of specific clinical signs and diagnostic immunohistochemical biomarkers, it is difficult for pathologists to distinguish MALToma from ocular RFH and ALH, which makes the clinical management of these conditions difficult. Here, we analyzed the clinical features of patients with ocular adnexal LPDs (n = 125) and investigated the structure of LFs in paraffin-embedded tissue samples using anti-CD23 and anti-IgD immunochemistry. We found that some clinical features including age, sex, and laterality were different among RFH, LFH, and MALToma. Additionally, immunohistochemistry revealed that the expression of IgD and CD23 was higher in RFH patients and decreased in patients with ALH and MALToma. Moreover, LFs in RFH were intact, whereas the structures of most LFs were disrupted in ALH. In MALToma specimens, few intact LFs were observed. In a further investigation, we combined the results for CD23/IgD immunohistochemistry and the structure of LFs to establish a scoring method for the differential diagnosis of LPDs. According to the BIOMED-2 protocol, we further detected IgH gene monoclonal rearrangement in 73 cases (35 RFH, 17 ALH, and 21 MALToma cases). The sensitivity of our scoring method, based on a comparison with the results of IgH gene monoclonal rearrangement detection, was 85.7% (18/21) for MALToma and 35.3% (6/17) for ALH. Our study provides a method that may be useful for the differential diagnosis of RFH, ALH, and MALToma.

Epithelial dysplasia of the stomach with gastric immunophenotype shows features of biological aggressiveness

BACKGROUND

Gastric dysplasia is classified as adenomatous/type I (intestinal phenotype) and foveolar or pyloric/type II (gastric phenotype) according to morphological (architectural and cytological) features. The immunophenotypic classification of dysplasia, based on the expression of the mucins, CD10 and CDX2, recognizes the following immunophenotypes: intestinal (MUC2, CD10, and CDX2); gastric (MUC5AC and/or MUC6, absence of CD10, and absent or low expression of CDX2); hybrid (gastric and intestinal markers); and null.

METHODS

Sixty-six cases of nonpolypoid epithelial dysplasia of the stomach were classified according to morphological features (histotype and grade) and immunophenotype. Immunohistochemical staining was performed with antibodies against MUC2, MUC5AC, MUC6, CD10, CDX2, chromogranin, synaptophysin, Ki-67, and TP53. HER2 alterations were analyzed by immunohistochemistry and silver-enhanced in situ hybridization.

RESULTS

By conventional histology, dysplasia was classified as adenomatous/intestinal (n = 42; 64 %) and foveolar or pyloric/gastric (n = 24; 36 %) and graded as low grade (n = 37; 56 %) or high grade (n = 29; 44 %). Immunophenotypic classification showed intestinal (n = 22; 33.3 %), gastric (n = 25; 37.9 %), hybrid (n = 17; 25.8 %), or null (n = 2; 3.0 %) phenotypes. In 20 cases a coexistent intramucosal carcinoma was identified. The intestinal immunophenotype was shown to be significantly associated with low-grade dysplasia (p = 0.001), high expression of CDX2 (p = 0.015), TP53 (p = 0.034), synaptophysin (p = 0.003), and chromogranin (p < 0.0001); the gastric immunophenotype was significantly associated with high-grade dysplasia (p = 0.001), high Ki-67 proliferative index (p = 0.05), and coexistence of intramucosal carcinoma (p = 0.013). HER2 amplification was observed in 3 cases, typed as gastric or hybrid.

CONCLUSIONS

Epithelial nonpolypoid dysplasia of the stomach with gastric immunophenotype shows features of biological aggressiveness and may represent the putative precursor lesion in a pathway of gastric carcinogenesis originated de novo from the native gastric mucosa, leading to gastric-type adenocarcinoma.

High-throughput mutation profiling identifies novel molecular dysregulation in high-grade intraepithelial neoplasia and early gastric cancers

BACKGROUND

There is still no widely accepted molecular marker available to distinguish between gastric high-grade intraepithelial neoplasia (HG-IEN) and invasive early gastric cancer (EGC).

METHODS

HG-IEN and EGC lesions coexisting in the same patient were manually microdissected from a series of 15 gastrectomies for EGC; 40 ng DNA was used for multiplex PCR amplification using the Ion AmpliSeq Cancer Panel, which explores the mutational status of hotspot regions in 50 cancer-associated genes.

RESULTS

Of the 15 EGCs, 12 presented at least one somatic mutation among the 50 investigated genes, and 6 of these showed multiple driver gene somatic mutations. TP53 mutations were observed in 9 cases; APC mutations were identified in 3 cases; and ATM and STK11 were mutated in 2 cases. Seven HG-IEN lesions shared an identical mutational profile with the EGC from the same patient; 13 mutations observed in APC, ATM, FGFR3, PIK3CA, RB1, STK11, and TP53 genes were shared by both HG-IEN and ECG lesions. CDKN2A, IDH2, MET, and RET mutations were observed only in EGC. TP53 deregulation was further investigated in an independent series of 75 biopsies corresponding to all the phenotypic lesions occurring in the EGC carcinogenetic cascade. p53 nuclear immunoreaction progressively increased along with the dedifferentiation of the lesions (P < 0.001). Overall, 18 of 20 p53-positive lesions showed a TP53 mutated gene.

DISCUSSION

Our results support the molecular similarity between HG-IEN and EGC and suggest a relevant role for TP53 in the progression to the invasive phenotype and the use of immunohistochemistry as a surrogate to detect TP53 gene mutations.

Individual risk stratification of gastric cancer: evolving concepts and their impact on clinical practice

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide and it mostly develops in long-standing inflammatory conditions, and Helicobacter pylori-gastritis, in particular. Despite the increasing understanding of both the phenotypic alterations and the molecular mechanisms occurring during GC multi-step carcinogenesis, no reliable biomarker is available to be reliably implemented into GC secondary prevention strategies. Multidisciplinary diagnostic approaches integrating endoscopy, serology, histology and molecular profiling currently appears as the most appropriate approach for patients' stratification into different GC risk classes.

Advanced precancerous lesions within the GI tract: the molecular background

The mainstream carcinogenic processes involved within the gastrointestinal tract are characterized by phenotypic multistep progression cascades that eventually result in full-blown cancers. In this scenario, the understanding of the molecular dysregulations underlying the precancerous lesions is increasing but still remains incomplete. However, in recent years, the enthusiastic rise of innovative technologies (i.e., next-generation sequencing, high-throughput microarray analysis, mass spectrometry based proteomics) and the unexpected discovery of new classes of biomarkers (i.e., miRNA, long-noncoding RNAs) prompted new strength in the exploration of the accurate and comprehensive molecular characterization of premalignant and malignant neoplastic lesions. The challenge ahead lies in the reliable identification of disease progression-specific targets to enable molecular testing in the clinical management of the secondary prevention of gastrointestinal cancers.

Lesions indefinite for intraepithelial neoplasia and OLGA staging for gastric atrophy

Gastric intraepithelial neoplasia (IEN; formerly dysplasia) is an advanced precancerous lesion. Lesions indefinite for IEN mimic the IEN phenotype but lack some morphologic attributes of IEN. Indefinite for IEN lesions may arise in native foveolae (atypical foveolar hyperproliferation [aFH]) or intestinalized glands (hyperproliferative intestinal metaplasia [HIM]). The clinicopathologic outcome of such lesions is debated. We retrospectively studied the clinicopathologic behavior of 129 consecutive indefinite for IEN lesions (HIM, 98; aFH, 31; median follow-up, 31 months) and correlated outcome with the extent and topography of mucosal atrophy (assessed by OLGA staging) at the initial endoscopy/biopsy. At enrollment, aFH never coexisted with severe/extensive atrophy (all cases were in low-risk OLGA stages [0-II]), whereas HIM was associated with low- and high-risk OLGA stages (0-II, 73; III-IV, 25). At follow-up, IEN was never documented among cases enrolled as aFH, while follow-up endoscopy/biopsy documented 6 neoplastic intraepithelial lesions among 98 cases of HIM (6%, all had high-risk OLGA stages at initial biopsy). OLGA staging can stratify indefinite for IEN lesions into different risk classes, potentially contributing to decisions for a patient-specific follow-up strategy.

Hepatitis C virus and human T-lymphotropic virus coinfection: epidemiological, clinical, laboratory and histopathological features

Twenty-four hepatitis C virus patients coinfected with human T-lymphotropic virus type 1 were compared with six coinfected with HTLV-2 and 55 with HCV alone, regarding clinical, epidemiological, laboratory and histopathological data. Fischer's discriminant analysis was applied to define functions capable of differentiating between the study groups (HCV, HCV/HTLV-1 and HCV/HTLV-2). The discriminant accuracy was evaluated by cross-validation. Alcohol consumption, use of intravenous drugs or inhaled cocaine and sexual partnership with intravenous drug users were more frequent in the HCV/HTLV-2 group, whereas patients in the HCV group more often reported abdominal pain or a sexual partner with hepatitis. Coinfected patients presented higher platelet counts, but aminotransferase and gamma-glutamyl transpeptidase levels were higher among HCV-infected subjects. No significant difference between the groups was seen regarding liver histopathological findings. Through discriminant analysis, classification functions were defined, including sex, age group, intravenous drug use and sexual partner with hepatitis. Cross-validation revealed high discriminant accuracy for the HCV group.

Updated diagnostic criteria on gastric epithelial dyspalsia

Large discrepancies exist between Eastern and Western countries in the diagnostic criteria for gastric epithelial dysplasia. With the purpose of a worldwide-accepted terminology and classification of precancerous lesions, Padova and Vienna classifications are established and reach a consensus that epithelial dysplasia is the earliest visible manifestation of neoplasia and the stage at which invasion has not yet occurred. So the primary term 'dysplasia' is confusing and misleading as gastric precancerous lesion. With more insight into dysplasia, new directions will be found to explore the pathogenesis, reversibility and therapy of dysplasia.