Cyclooxygenase-2 polymorphisms and the risk of esophageal adeno-or squamous cell carcinoma

AIM： TO determine whether -1195 A→G and/or -765 G→C polymorphisms in Cyclooxygenase-2 CCOX-2） may have a risk modifying effect on the development of esophageal carcinoma in a Dutch Caucasian population. METHODS： Two study groups were recruited, 252 patients with esophageal carcinoma and 240 healthy controls, matched for race, age, gender and recruiting area. DNA was isolated from whole blood and used for genotyping. PCR products were digested with restriction enzymes and products were analyzed by agarose gel electrophoresis. Odds ratios （OR） and 95% confidence intervals （CI） were estimated. RESULTS： The distribution of the -1195A→G polymorphism was significantly different in esophageal cancer patients compared to controls. The -1195 GG genotype resulted in a higher risk of developing esophageal adenocarcinoma （OR = 3.85, 95% CI： 1.45-10.3） compared with the -1195AA genotype as a reference. The -765 G→C genotype distribution was not different between the two groups. The GG/ GG haplotype was present more often in esophageal adenocarcinoma patients than in controls （OR = 3.45, 95% CI： 1.24-9.58; with AG/AG as a reference）. The same trends were observed in patients with squamous cell carcinomas, however, the results did not reach statistical significance. CONCLUSION： Presence of the COX-2 -1195 GG genotype and of the GG/GG haplotype may result in a higher risk of developing esophageal carcinoma.

Microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence

AIM: To investigate the microsatellite alterations in phenotypically normal esophageal squamous epithelium and metaplasia-dysplasia-adenocarcinoma sequence. METHODS: Forty-one specimens were obtained from esophageal cancer (EC) patients. Histopathological assessment identified 23 squamous cell carcinomas (SCC) and 18 adenocarcinomas (ADC), including only 8 ADC with Barrett esophageal columnar epithelium (metaplasia) and dysplasia adjacent to ADC. Paraffin-embedded normal squamous epithelium, Barrett esophageal columnar epithelium (metaplasia), dysplasia and esophageal tumor tissues were dissected from the surrounding tissues under microscopic guidance. DNA was extracted using proteinase K digestion buffer, and DNA was diluted at 1:100, 1:1000, 1:5000, 1:10 000 and 1:50 000, respectively. Seven microsatellite markers (D2S123, D3S1616, D3S1300, D5S346, D17S787, D18S58 and BATRII loci) were used in this study. Un-dilution and dilution polymerase chainreactions (PCR) were performed, and microsatellite analysis was carried out. RESULTS: No statistically significant difference was found in microsatellite instability (MSI) and loss of heterozygosity (LOH) of un-diluted DNA between SCC and ADC. The levels of MSI and LOH were high in the metaplasia-dysplasia-adenocarcinoma sequence of diluted DNA. The more the diluted DNA was, the higher the rates of MSI and LOH were at the above 7 loci, especially at D3S1616, D5S346, D2S123, D3S1300 and D18S58 loci. CONCLUSION: The sequence of metaplasia-dysplasia-adenocarcinoma is associated with microsatellite alterations, including MSI and LOH. The MSI and LOH may be the early genetic events during esophageal carcinogenesis, and genetic alterations at the D3S1616, D5S346 and D3S123 loci may play a role in the progress of microsatellite alterations.

Overexpression of Ets-like protein 1 in human esophageal squamous cell carcinoma

AIM: To study the expression pattern of Ets-like protein 1 (Elk-1) in human esophageal squamous cell carcinoma (ESCC) and to analyze its relationship with clinicopathologic parameters. METHODS: The expression of Elk-1 in fresh esophageal cancer tissues and their corresponding normal mucosae was detected immunohistochemically (IHC) by means of tissue microarray (TMA). Its correlation with clinical characteristics was evaluated and analyzed by univariate analysis. All statistical analyses were performed by SPSS version 13.0. RESULTS: Expression level of transcription factor Elk-1 increased in 78.5% (84/107) ESCC tissues compared with their matched normal esophageal epithelium. However, the expression of Elk-1 did not show any obvious correlation with degree of differentiation of esophageal carcinoma (in well-differentiated, moderately-differentiated and poorly-differentiated tumors, the increased expression was 7/8, 60/74, and 19/25, respectively, P > 0.05). Moreover, no obvious correlation was found with lymph node metastasis and depth of invasion. CONCLUSION: Increased expression of transcription factor Elk-1 may play an important role in esophageal carcinogenesis.

Identification of the layered morphology of the esophageal wall by optical coherence tomography

AIM： To assess each layer of the optical coherence tomography （OCT） image of the esophageal wall with reference to the histological structure, METHODS： Resected specimens of fresh pig esophagus was used as a model for the esophageal wall. We injected cyanoacrylate adhesive into the specimens to create a marker, and scanned them using a miniature OCT probe. The localization of these markers was assessed in the OCT images. Then we compared the OCT-imaged morphology with the corresponding histological section, guided by the cyanoacrylate adhesive markers. We prepared a second set of experiments using nylon sutures as markers. RESULTS： The OCT image of the esophageal specimen has a clear five-layered morphology. First, it consisted of a relatively less reflective layer; second, a more reflective layer; third, a less reflective layer; fourth, a more reflective layer; and fifth, a less reflective layer. Comparing the OCT images with marked histological sections showed that the first layer corresponded to stratified squamous epithelium; the second to lamina propria; the third to muscularis mucosa; fourth, submucosa; and fifth, muscularis propria with deeper structures of the esophageal wa CONCLUSION： We demonstrated that the OCT image of the normal esophageal wall showed a five- layered morphology, which corresponds to histological esophageal wall components.

Downregulation of miR-503 Promotes ESCC Cell Proliferation,Migration,and Invasion by Targeting Cyclin D1

Esophageal squamous cell carcinoma （ESCC） is one of the most aggressive cancers in China, but the underlying molecular mechanism of ESCC is still unclear. Involvement of micro- RNAs has been demonstrated in cancer initiation and progression. Despite the reported function of miR-503 in several human cancers, its detailed anti-oncogenic role and clinical significance in ESCC remain undefined. In this study, we examined miR-503 expression by qPCR and found the downregulation of miR-503 expression in ESCC tissue relative to adjacent normal tissues. Fur- ther investigation in the effect of miR-503 on ESCC cell proliferation, migration, and invasion showed that enhanced expression of miR-503 inhibited ESCC aggressive phenotype and overexpres- sion of CCND1 reversed the effect of miR-503-mediated ESCC cell aggressive phenotype. Our study further identified CCND1 as the target gene of miR-503. Thus, miR-503 functions as a tumor suppressor and has an important role in ESCC by targeting CCND1.

Patient-derived xenograft platform of OSCC： a renewable human bio-bank for preclinical cancer research and a new co-clinical model for treatment optimization

Advances in next-generation sequencing and bioinformatics have begun to reveal the complex genetic landscape in human cancer genomes, including oral squamous cell carcinoma （OSCC）. Sophisticated preclinical models that fully represent intra- and inter-tumoral heterogeneity are required to understand the molecular diversity of cancer and achieve the goal of personalized therapies. Patient-derived xenograft （PDX） models generated from human tumor samples that can retain the histological and genetic features of their donor tumors have been shown to be the preferred preclinical tool in translational cancer research compared with other conventional preclinical models. Specifically, genetically well-defined PDX models can be applied to accelerate targeted antitumor drug development and biomarker discovery. Recently, we have successfully established and characterized an OSCC PDX panel as part of our tumor bio-bank for translational cancer research. In this paper, we discuss the establishment, characterization, and preclinical applications of the PDX models. In particular, we focus on the classification and applications of the PDX models based on validated annotations, including clinicopathological features, genomic profiles, and pharmacological testing information. We also explore the translational value of this well-annotated PDX panel in the development of co-clinical trials for patient stratification and treatment optimization in the near future. Although various limitations still exist, this preclinical approach should be further tested and improved.