Biologic and clinical significance of squamous epithelial dysplasia of the esophagus

Diagnosis and Clinical Management of Esophageal Squamous Dysplasia

Esophageal squamous cell carcinoma is the seventh most common cancer and the sixth most common cause of cancer death worldwide. Esophageal squamous dysplasia is the only histopathology that predicts the development of esophageal squamous cell carcinoma. It is difficult to identify esophageal squamous dysplasia by conventional endoscopy; however, Lugol chromoendoscopy is useful for the diagnosis of such a lesion. In addition, advance endoscopic detection techniques, such as image-enhanced endoscopy (especially, narrow-band imaging), magnifying endoscopy, and endocytoscopy, are helpful in detecting esophageal squamous dysplasia. Similar to the treatment for early esophageal cancer, endoscopic resection such as endoscopic mucosal resection and endoscopic submucosal dissection is the choice of treatment for esophageal squamous dysplasia. This review discusses esophageal squamous dysplasia in detail, especially in terms of endoscopic diagnosis and clinical management.

Chromosomal aneuploidies and combinational fluorescence in situ hybridization probe panels are useful for predicting prognosis for esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a common cancer type in China. In this study, we aimed to develop aneuploidy markers for diagnosis and prognosis of ESCC.

METHODS

Chromosomal aneuploidies were detected in 493 primary tumors and 61 precancerous lesions by fluorescence in situ hybridization with chromosome enumeration probes (CEP), and cut-off values were set by receiver operating characteristic (ROC) curves.

RESULTS

According to the cut-off values, chromosomes 3, 8, 10, 12, 17 and 20 presented frequent gains, with rates of 70.1, 69.7, 58.9, 66.9, 67.5 and 77.2 % in tumors and of 32.1, 26.8, 33.9, 41.2, 44.0 and 42.0 % in precancerous lesions. Loss of chromosome Y was detected in 72.0 % of male patients. An optimal four-probe panel CEP3/12/17/20 was established for detecting ESCC (sensitivity: 86.1 %), and CEP3/10/12/20 for precancerous lesions (sensitivity: 48.0 %). Gain of CEP8 was significantly correlated with lymph node metastasis (LNM) and late stages (P = 0.002 and 0.001), and loss of CEPY with age (P = 0.002, male). Kaplan-Meier survival curves indicated that patients with positive CEP10/17 (pT1 + T2, P = 0.041) and CEP8/17 (stages IIb + III + IV, P = 0.002) had poor overall survival. Combinations of LNM/stage and CEP panels could divide patients into more subgroups, including LNM + CEP3/17, LNM + CEP10/17, LNM + CEP3/10/17, stage + CEP3/17, stage + CEP10/17 and stage + CEP3/10/17 (P = 0.0004, 0.0003, 0.0001, 0.005, 0.001 and 0.0008, respectively). Multivariate Cox regression analysis confirmed that the above combinational models were independent prognostic factors.

CONCLUSIONS

Our data suggest that the combinational probe sets may have potential for detection and prognostic prediction of ESCC.

Chromosomal instability associated with global DNA hypomethylation is associated with the initiation and progression of esophageal squamous cell carcinoma

BACKGROUND

Global DNA hypomethylation is associated with increased chromosomal instability and plays an important role in tumorigenesis. The methylation status of the long interspersed nuclear element-1 (LINE-1) element is a useful surrogate marker for global DNA methylation. Although LINE-1 hypomethylation is recognized as a poor prognostic marker, the correlation of LINE-1 methylation level with tumor suppressor gene mutation, chromosomal instability, and clinical significance in esophageal squamous cell carcinoma (ESCC) remains unclear.

METHODS

Using resected tumor tissues and the corresponding normal esophageal mucosa from 105 patients with ESCC, bisulfite pyrosequencing analysis was performed to quantify the LINE-1 methylation levels. p53 mutations in exons two to ten were detected by polymerase chain reaction direct sequencing. Chromosomal instability was assessed by single nucleotide polymorphism array comparative genomic hybridization analysis.

RESULTS

The LINE-1 methylation level of ESCC was significantly lower than matched normal mucosa. LINE-1 methylation levels of normal mucosa from the esophagus had a significant inverse correlation with both cigarette smoking and alcohol consumption of the study subjects. LINE-1 hypomethylation of ESCC was significantly associated with lymph node metastasis, lymphovascular invasion, the frequency of p53 mutation and poor survivability. The LINE-1 methylation levels in ESCC had a significant inverse association with the percentage of copy number alterations in the whole genome, mirroring chromosomal instability.

CONCLUSIONS

Our results suggested that whole genome hypomethylation caused by chronic inflammation could initiate carcinogenesis of esophageal squamous cells through chromosomal instability. In addition, chromosomal instability associated with the global hypomethylation might correlate highly with the progression of ESCC.

Copy-neutral loss of heterozygosity at the p53 locus in carcinogenesis of esophageal squamous cell carcinomas associated with p53 mutations

PURPOSE

LOH at the p53 locus has been reported to be associated with esophageal squamous cell carcinogenesis. The aim of this study is to identify potential mechanisms resulting in LOH around the p53 locus in its carcinogenesis.

EXPERIMENTAL DESIGN

We investigated 10 esophageal cancer cell lines and 91 surgically resected specimens, examining them for LOH at the p53 locus on chromosome 17. We examined the p53 gene by using microsatellite analysis, comparative genomic hybridization (CGH), FISH, and single-nucleotide polymorphism-CGH (SNP-CGH).

RESULTS

In an analysis of specimens by microsatellite markers, a close positive correlation was found between p53 mutations and LOH at the p53 locus (P < 0.01). Although four cell lines were found to be homozygous for p53 mutations, LOH at the p53 locus was not detected by CGH. Among two p53 mutant cancer cell lines and five p53 mutant/LOH cancer specimens analyzed by FISH, both the cell lines and four of the specimens exhibited no obvious copy number loss at the p53 locus. SNP-CGH analysis, which allows both determination of DNA copy number and detection of copy-neutral LOH, showed that LOHs without copy number change were caused by whole or large chromosomal alteration.

CONCLUSIONS

LOH without copy number change at the p53 locus was observed in p53 mutant esophageal squamous cell carcinomas. Our data suggest that copy-neutral LOH occurring as a result of chromosomal instability might be the major mechanism for inactivation of the intact allele in esophageal squamous cell carcinogenesis associated with p53 mutation.

Neoplasia without dysplasia: lessons from Barrett esophagus and other tubal gut neoplasms

CONTEXT

Classic pathology teaching emphasizes that neoplastic lesions of the gastrointestinal tract are characterized by architectural and cytologic abnormalities that distinguish it from normal tissue. Recent studies suggest that many important-and in some cases clonal-molecular abnormalities that lead to dysregulation of cell proliferation and differentiation (neoplasia) occur before morphologic expression of dysplasia.

OBJECTIVE

To summarize the biologic and pathologic features of preneoplastic conditions of the tubal gut that reveal evidence of neoplastic alteration, but without the traditional morphologic features of dysplasia, in order to provide guidance on how to identify these lesions. Particular attention is given to Barrett esophagus, a chronic inflammatory condition in which early molecular and morphologic events that drive carcinogenesis are best understood.

DATA SOURCES

Selected references and abstracts were obtained by a PubMed (US National Library of Medicine) search by using the search headings neoplasia, preneoplasia, dysplasia, adenoma, serrated polyps, and Barrett's esophagus between the years 1980 and 2009.

CONCLUSIONS

Many types of lesions throughout the tubal gut fulfill the most basic and classic principles of a neoplastic precursor lesion but lack conventional morphologic evidence of dysplasia and/or maintain the capacity for cell differentiation and maturation. All of these lesions, such as squamous dysplasia of the esophagus, dysplasia in Barrett esophagus, and hyperplastic/serrated polyps of the colon, represent early neoplastic precursor lesions but without conventional histologic features of dysplasia. It is important for pathologists to be aware of these lesions, both for diagnostic and prognostic purposes, but also so that future studies can be performed with regard to risk stratification of patients.

The presence of aberrant DNA methylation in noncancerous esophageal mucosae in association with smoking history: a target for risk diagnosis and prevention of esophageal cancers

BACKGROUND

Esophageal squamous cell carcinomas (ESCCs) tend to have multiple primary lesions, and it is believed that they arise from background mucosae with accumulation of genetic/epigenetic alterations. In this study, the objective was to elucidate the effects of smoking and drinking on the accumulation of epigenetic alterations in background mucosae.

METHODS

Genes that are silenced in human ESCCs were searched for by treating 3 ESCC cell lines with the demethylating agent, 5-aza-2'-deoxycytidine and performing oligonucleotide microarrays. Methylation levels were analyzed by quantitative methylation-specific polymerase chain reaction analysis of 60 ESCCs and their corresponding background mucosae.

RESULTS

Forty-seven genes were identified as methylation-silenced in at least 1 of the 3 ESCC cell lines, and 14 of those genes (claudin 6 [CLDN6]; G protein-coupled receptor 158 [GPR158]; homeobox A9 [HOXA9]; metallothionein 1M [MT1M]; neurofilament, heavy polypeptide 200 kDa [NEFH]; plakophilin 1 [PKP1]; protein phosphatase 1, regulatory [inhibitor] subunit 14A [PPP1R14A]; pyrin domain and caspase recruitment domain containing [PYCARD]; R-spondin family, member 4 [RSPO4]; testis-specific protein, Y-encoded-like 5 [TSPYL5]; ubiquitin carboxyl-terminal esterase L1 [UCHL1]; zinc-finger protein 42 homolog [ZFP42]; zinc-finger protein interacting with K protein 1 homolog [ZIK1]; and zinc-finger and SCAN domain containing 18 [ZSCAN18]) were used as markers. In the background mucosae, methylation levels of 5 genes (HOXA9, MT1M, NEFH, RSPO4, and UCHL1) had significant correlations with smoking duration (rho=.268; P=.044; rho=.405; P=.002; rho=.285; P=.032; rho=.300; P=.024; and rho=.437; P=.001, respectively). In contrast, an inverse correlation between PYCARD methylation levels and alcohol intake was observed (rho=-.334, P=.025) among individuals with the inactive aldehyde dehydrogenase 2 (ALDH2) genotype.

CONCLUSIONS

The current results suggested that ESCCs developed from an epigenetic field for cancerization, which was induced by exposure to carcinogenic factors, such as tobacco smoking. The epigenetic field defect will be a novel target for risk diagnosis and prevention of ESCCs.

Squamous dysplasia and other precursor lesions related to esophageal squamous cell carcinoma

Squamous cell carcinoma is the most common tumor of the esophagus worldwide, and it is believed to develop through a sequence of dysplastic precursor lesions, which can be detected both endoscopically and microscopically. There are no published guidelines regarding treatment for dysplasia; however, most authorities recommend increased endoscopic surveillance, with biopsies, for patients with flat low-grade dysplasia and endoscopic mucosal resection, endoscopic submucosal dissection, or esophagectomy for patients with high-grade dysplasia. Future studies are needed to define appropriate endoscopic surveillance frequencies for patients with premalignant lesions of the esophagus. This article discusses squamous dysplasia in detail, which is the most important and well-described risk factor for squamous cell carcinoma of the esophagus.

Cribado del carcinoma escamoso de esófago en población de riesgo

Together with adenocarcinoma, epidermoid esophageal carcinoma is the most clinically important neoplasm of the esophagus. Because of the low incidence of epidermoid esophageal carcinoma in the general population, strategies for its early diagnosis are not a priority compared with other neoplasms. However, because survival is low when the disease is diagnosed in symptomatic patients (less than 20% at 5 years), methods for its early diagnosis should be investigated. The use of cytology or Lugol chromoendoscopy in countries with a high incidence of epidermoid carcinoma or in individuals at increased risk (mainly alcoholics and smokers) has allowed early diagnosis and potentially curative treatment, substantially increasing life expectancy in this group of patients. These results should stimulate the evaluation and eventual implementation of programs to achieve early diagnosis and therefore greater survival in patients with epidermoid esophageal carcinoma in Western countries.

DARPP-32 expression arises after a phase of dysplasia in oesophageal squamous cell carcinoma

This is the first report to correlate DARPP-32 immunoreactivity (dopamine and cAMP-regulated phosphoprotein, M_r 32 000) to clinicopathological status in human cancer. DARPP-32 is recognised as a neuronal protein. A recent study demonstrated that DARPP-32, and a truncated isoform t-DARPP, are overexpressed in gastric carcinoma during the process of carcinogenesis. The biological function of DARPP-32, however, is still unclear. The purpose of this study was to clarify the roles of DARPP-32 and t-DARPP in oesophageal squamous cell carcinoma (OSCC). Initially, we investigated DARPP-32 and t-DARPP expression in OSCC cell lines by Reverse transcription–polymerase chain reaction and Western blot. DARPP-32 expression was observed in four out of seven (57.1%) cell lines, but t-DARPP expression was not observed in any cell lines. In oesophageal tissue sample, DARPP-32 expression was observed in four out of seven (57.1%) tumour tissues, while t-DARPP was not observed in any tissues. Subsequently, DARPP expression was assessed by immunohistochemistry, using a polyclonal antibody, in tissue sections from 122 patients with primary OSCC. DARPP immunoreactivity was not observed in any normal oesophageal mucous membranes. On the other hand, positive DARPP immunostaining was detected in 37 patients (30.3%) and correlated inversely with pathologic stage (P=0.0284), pT (P=0.0438), pN (P=0.0303) and tumour size (P=0.012). The overall survival rate was worse in patients with DARPP-negative tumours than in patients with DARPP-positive tumours (P=0.0453). Interestingly, DARPP expression was observed in only one out of 45 cases of dysplasia. These observations suggest that DARPP-32 (rather than t-DARPP) expression arises after a phase of dysplasia in OSCC, and that tumours expressing DARPP-32 progress less rapidly than DARPP-32-negative tumours.