Characterisation of p53 status at the gene, chromosomal and protein levels in oesophageal adenocarcinoma

Opium Consumption and the Incidence of Cancer: Does Opium Account as an Emerging Risk Factor for Gastrointestinal Cancer?

PURPOSE

Some epidemiological studies have shown an association between opium consumption and the incidence of gastrointestinal (GI) cancer. The present study was designed to investigate the effects of opium on the initiation of GI cancer in rats.

METHODS

Forty-five rats were randomly divided into three groups; each received different treatment for 40 weeks. The rats in group 1 received purified water, while animals in group 2 were treated with 5 mg/kg diethylnitrosamine (DEN) orally for 8 weeks and continued with purified water by the end of the experiment. The third experimental group received 300 mg/kg opium for 16 weeks and then continued with 50 mg/kg phenobarbital by the end of the 40th week. The growth of tumors in the treated groups was assessed by histological changes and the up/down expression of p53, cdkn1, cdk2, e-cdh, and n-cdh genes in different parts of GI tract.

RESULTS

Histological examinations revealed that DEN was able to induce the growth of tumor in GI tract as shown by active mitotic figure in different regions of GI system and hyperplasia of hepatocytes associated with infiltration of inflammatory cells, intestinal villous hypertrophy, and colorectal adenoma. There was also significant (p < 0.05) overexpression of p53, cdk2, and n-Cdh genes in different parts of digestive system in DEN-treated group. However, these pathological changes and the degradation of gene expression were not observed in the opium-treated group.

CONCLUSION

The results of this study suggest that the opium does not promote the initiation of cancer in GI tract.

Microsatellite instability in metaplasia-dysplasia-adenocarcinoma sequence of Barrett esophagus: a retrospective study

Aim

To analyze the loss of mismatch repair (MMR) system protein expression in metaplasia-dysplasia-adenocarcinoma sequence of Barrett esophagus (BE).

Methods

This study retrospectively analyzed the data from 70 patients with pathohistological diagnosis of BE or esophageal adenocarcinoma (EAC) treated at the Clinical Department of Pathology and Cytology, University Hospital Center Zagreb, from January 2009 to January 2011. Patients were divided into three groups: BE without dysplasia (22 patients), BE with dysplasia (37 patients), and EAC (11 patients). Immunohistochemical expression of MutL homologue 1 (MLH1), MutS homologue 2 (MSH2), postmeiotic segregation increased 2 (PMS2), and MutS homologue 6 (MSH6) of DNA MMR system was measured and compared with tumor protein p53 expression.

Results

A total of 81.8% and 81.8% patients with EAC, 32.4% and 35.1% patients with dysplasia, and 50% and 54.5% patients without dysplasia had loss of MLH1 and PMS2 expression, respectively. Patients with EAC and patients with dysplasia did not have loss of MSH2 and MSH6 expression, and 18.2% patients without dysplasia had loss of MSH2 and MSH6 expression. There was a strong positive correlation between MLH1 and PMS2 expression (Spearman ρ 0.97; P < 0.001) and between MSH2 and MSH6 expression (Spearman ρ 0.90, P < 0.001) in the entire sample and in all BE groups. No significant correlations of MLH1 and PMS2 with p53 expression were found, except in dysplasia group (φ 0.402, P = 0.030 for MSH1; φ 0.371, P = 0.042 for PMS2).

Conclusion

Although we demonstrated considerable loss of MLH1 and PMS2 expression in BE-associated carcinoma sequence, due to the retrospective study design and low number of patients we cannot conclude that MLH1 and PMS2 can be used as biomarkers for patient surveillance and therapy-making decisions.

Oxford Centre for Evidence-based Medicine level of evidence: 3

Targeted Single Gene Mutation in Esophageal Adenocarcinoma

Esophageal adenocarcinoma is heterogeneous and studies have reviewed many important mutations that contribute to the pathogenesis of the cancer. These discoveries have helped paved the way into identifying new gene markers or gene targets to develop novel molecular directed therapy for better patient outcomes in esophageal adenocarcinoma. Despite the recent bloom in next-generation sequencing, Sanger sequencing still represents the gold standard method for the study of the driver genes in esophageal adenocarcinoma. This chapter focuses on the sequencing techniques in identification of single gene mutations.

Loss of P16 in Esophageal Adenocarcinoma Detected by Fluorescence in situ Hybridization and Immunohistochemistry

Molecular biology of esophageal adenocarcinoma (EAC) is not fully elucidated. The aim of this study was to assess the expression of cycle regulator and tumor suppressor p16 in esophageal adenocarcinoma. The expression of p16 at protein and gene level was investigated using immunohistochemistry and fluorescence in situ hybridization in thirteen EAC specimens obtained by endoscopic biopsies and surgical resections. The mean age of enrolled patients was 62 years and a male predominance was observed. Loss of p16 protein expression was detected in 77% of the cases and loss of p16 gene was found in 69% of cases as hemizygous deletion was the most common. Significant correlation was found between the absence of p16 protein expression and p16 allelic loss. Cell cycle disturbances seem to play role in the EAC carcinogenesis and probably p16 gene deletions are connected with the loss of p16 protein expression.

BOB CAT: A Large-Scale Review and Delphi Consensus for Management of Barrett's Esophagus With No Dysplasia, Indefinite for, or Low-Grade Dysplasia

OBJECTIVES

Barrett's esophagus (BE) is a common premalignant lesion for which surveillance is recommended. This strategy is limited by considerable variations in clinical practice. We conducted an international, multidisciplinary, systematic search and evidence-based review of BE and provided consensus recommendations for clinical use in patients with nondysplastic, indefinite, and low-grade dysplasia (LGD).

METHODS

We defined the scope, proposed statements, and searched electronic databases, yielding 20,558 publications that were screened, selected online, and formed the evidence base. We used a Delphi consensus process, with an 80% agreement threshold, using GRADE (Grading of Recommendations Assessment, Development and Evaluation) to categorize the quality of evidence and strength of recommendations.

RESULTS

In total, 80% of respondents agreed with 55 of 127 statements in the final voting rounds. Population endoscopic screening is not recommended and screening should target only very high-risk cases of males aged over 60 years with chronic uncontrolled reflux. A new international definition of BE was agreed upon. For any degree of dysplasia, at least two specialist gastrointestinal (GI) pathologists are required. Risk factors for cancer include male gender, length of BE, and central obesity. Endoscopic resection should be used for visible, nodular areas. Surveillance is not recommended for <5 years of life expectancy. Management strategies for indefinite dysplasia (IND) and LGD were identified, including a de-escalation strategy for lower-risk patients and escalation to intervention with follow-up for higher-risk patients.

CONCLUSIONS

In this uniquely large consensus process in gastroenterology, we made key clinical recommendations for the escalation/de-escalation of BE in clinical practice. We made strong recommendations for the prioritization of future research.

Signaling pathways in the molecular pathogenesis of adenocarcinomas of the esophagus and gastroesophageal junction

Esophageal adenocarcinoma develops in response to severe gastroesophageal reflux disease through the precursor lesion Barrett esophagus, in which the normal squamous epithelium is replaced by a columnar lining. The incidence of esophageal adenocarcinoma in the United States has increased by over 600% in the past 40 years and the overall survival rate remains less than 20% in the community. This review highlights some of the signaling pathways for which there is some evidence of a role in the development of esophageal adenocarcinoma. An increasingly detailed understanding of the biology of this cancer has emerged recently, revealing that in addition to the well-recognized alterations in single genes such as p53, p16, APC, and telomerase, there are interactions between the components of the reflux fluid, the homeobox gene Cdx2, and the Wnt, Notch, and Hedgehog signaling pathways.

Whole genome expression array profiling highlights differences in mucosal defense genes in Barrett's esophagus and esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) has become a major concern in Western countries due to rapid rises in incidence coupled with very poor survival rates. One of the key risk factors for the development of this cancer is the presence of Barrett's esophagus (BE), which is believed to form in response to repeated gastro-esophageal reflux. In this study we performed comparative, genome-wide expression profiling (using Illumina whole-genome Beadarrays) on total RNA extracted from esophageal biopsy tissues from individuals with EAC, BE (in the absence of EAC) and those with normal squamous epithelium. We combined these data with publically accessible raw data from three similar studies to investigate key gene and ontology differences between these three tissue states. The results support the deduction that BE is a tissue with enhanced glycoprotein synthesis machinery (DPP4, ATP2A3, AGR2) designed to provide strong mucosal defenses aimed at resisting gastro-esophageal reflux. EAC exhibits the enhanced extracellular matrix remodeling (collagens, IGFBP7, PLAU) effects expected in an aggressive form of cancer, as well as evidence of reduced expression of genes associated with mucosal (MUC6, CA2, TFF1) and xenobiotic (AKR1C2, AKR1B10) defenses. When our results are compared to previous whole-genome expression profiling studies keratin, mucin, annexin and trefoil factor gene groups are the most frequently represented differentially expressed gene families. Eleven genes identified here are also represented in at least 3 other profiling studies. We used these genes to discriminate between squamous epithelium, BE and EAC within the two largest cohorts using a support vector machine leave one out cross validation (LOOCV) analysis. While this method was satisfactory for discriminating squamous epithelium and BE, it demonstrates the need for more detailed investigations into profiling changes between BE and EAC.

Association of p53/p21 expression with cigarette smoking and prognosis in esophageal squamous cell carcinoma patients

AIM: To investigate the expression of p53 and p21 and associations with possible risk factors, such as cigarette smoking, in esophageal squamous cell carcinoma (ESCC) in northeastern Iran, a region with a high incidence of ESCC.

METHODS: The expression of p53 and p21 proteins was investigated immunohistochemically in tumor tissue from 80 ESCC patients and in 60 available paraffin-embedded blocks of adjacent normal specimens from the cases, along with normal esophageal tissue from 80 healthy subjects.

RESULTS: Positive expression of p53 protein was detected in 56.2% (45/80) of ESCC cases, and in none of the normal esophageal tissue of the control group (P < 0.001). Furthermore, 73.8% (59/80) of ESCC cases and 43.8% (35/80) of controls had positive expression of p21 protein (P < 0.001). Cigarette smoking was significantly associated with p53 over-expression in ESCC cases (P = 0.010, OR = 3.64; 95% CI: 1.32-10.02). p21 over-expression was associated with poorer clinical outcome among the ESCC patients (P = 0.009).

CONCLUSION: Over-expression of p53 in association with cigarette smoking may play a critical role in ESCC carcinogenesis among this high-risk population of northeastern Iran. Furthermore, p21 over-expression was found to be associated with poor prognosis, specifically in the operable ESCC patients.

Genetic diagnosis of patients with esophageal cancer using FISH

This study aimed to the clarify the diagnostic efficacy of fluorescence in situ hybridization (FISH) in Kazakh patients with esophageal cancer (EC). FISH was compared with the pathological examination of biopsy specimens with DNA probes. We enrolled 20 patients, of which 15 were males and 5 females, with an average age of 58.3 years, who had abnormal esophaguses on barium radiological digital imaging. Touch preparations were performed on biopsy specimens from all of the patients and were examined using FISH for chromosomal abnormalities. We compared the FISH results with the pathology slides stained with hematoxylin and eosin. Classification, according to pathology, identified 2 cases of class II, 3 cases of IIIa, 1 case of IIIb, 2 cases of IV, 12 cases of class V and no cases of class I. The cases classified as class IIIb or higher were considered to be positive for cancer. Using histopathology, 10 cases were diagnosed with squamous cell carcinoma and 5 were diagnosed as adenocarcinoma, with one case being false-negative. Thus, the sensitivity of the pathological examination was 93% and the specificity was 100%. Using FISH, 16 cases showed aberrant copy numbers in either chromosome 3 or 17. By comparison, pathology did not reveal any false-positive or false-negative cases with a sensitivity and specificity of 100%. The centromeres of chromosome 3 copy numbers was significantly higher (p=0.035) than the centromeres of chromosome 17. Our study compared FISH to diagnose aneusomic esophageal cancer cells with the pathology of biopsied tissue. Our findings suggest that FISH is a useful and objective assay for the detection of malignant cells of esophageal cancer. In our study, the centromeres of chromosome 3 was the more sensitive probe for the diagnosis of esophageal cancer in Kazakh patients.

Immunohistochemical analysis of selected molecular markers in esophagus precancerous, adenocarcinoma and squamous cell carcinoma in Iranian subjects

BACKGROUND

The molecular and cellular mechanisms linking chronic inflammation and gastrointestinal malignancy are not known with certainty.

AIM

To investigate changes in potential causative factors during progression of esophagus cancer in a population living in high-risk area in Iran.

SUBJECTS

Formalin-fixed, paraffin-embedded esophageal specimens (n=87) from patients with gastroesophageal reflux disease (GERD), Barrett's metaplasia, adenocarcinoma (ADC) and squamous cells carcinoma (SCC) were collected based on their pathological diagnosis.

METHODS

Immunohistochemical (IHC) technique was used to study tissue accumulation of P53, P21, cyclooxygenase-2 (COX-2), glutathione S-transferase-P (GST-Pi) and nitrotyrosine (NT) in patients and controls.

RESULTS

P53 expression was not detected in esophageal tissues from normal and GERD samples, whereas it was found positive in Barrett's, ADC, and SCC samples. P21 positive sample was relatively higher in ADC patients as compared to that in SCC (ADC: 52.6%; SCC: 25%). GST-Pi expression was equally accumulated in all the samples. NT was predominantly expressed in ADC (72.7%). COX-2 expression was significantly higher in Barrett's (60.0%) and ADC (66.6%) as compared to that in GERD, SCC and normal. These data were further confirmed by detecting the scores of immunostainings in all the positive samples.

CONCLUSION

The pathological changes in ADC and SCC samples which were associated with increasing frequency of NT and COX-2 provides further evidence for involvement of these inflammatory factors in progression of esophagus cancer.

Advances in biological characteristics of p53 gene and its role in gastrointestinal tumors

With the progression of current genetic research, tumor-specific gene detection has become an important method to identify tumor patients; meanwhile, gene therapy or gene-targeted therapy, which is becoming a novel approach of tumor treatment, has brought a new hope for the final cure of malignant tumors. In this article, we review the characteristics of tumor-associated gene p53 and its role in gastrointestinal tumors.

Cigarette smoking, body mass index, gastro-esophageal reflux disease, and non-steroidal anti-inflammatory drug use and risk of subtypes of esophageal and gastric cancers by P53 overexpression

A number of risk factors for esophageal and gastric cancers have emerged, yet little is known whether risk factors map to molecular tumor markers such as overexpression of the tumor suppressor TP53. Using a US multicenter, population-based case-control study (170 cases of esophageal adenocarcinomas, 147 gastric cardia adenocarcinomas, 220 non-cardia gastric adenocarcinomas, and 112 esophageal squamous cell carcinomas), we examined whether the risk associated with cigarette smoking, body mass index (BMI), gastroesophageal reflux disease (GERD), and non-steroidal anti-inflammatory drug (NSAID) use varied by P53 overexpression. We defined P53 overexpression through immunohistochemistry of paraffin-embedded tumor tissues, using cutpoints based on percent of cells positive. Polytomous logistic regression was used to assess differences between each case group (defined by tumor subtype and P53 expression) and the control group by risk factors. The proportion of cases overexpressing P53 by tumor subtype was 72% for esophageal adenocarcinoma, 69% for gastric cardia adenocarcinoma, 52% for non-cardia gastric adenocarcinoma, and 67% for esophageal squamous cell carcinoma. For most tumor subtypes, we found little difference in risk factors by tumor P53 overexpression. For non-cardia gastric cancer however, an association with cigarette smoking was suggested for tumors that do not overexpress P53, whereas larger BMI was related to adenocarcinomas that overexpress P53 versus no overexpression. Overall, this study did not find a clear relationship between P53 protein overexpression and the known risk factors for subtypes of esophageal and gastric cancers. Further research on these tumors is needed to identify molecular markers associated with variations in the risk factor profiles.

Human papillomavirus infection in Barrett's oesophagus in the UK: an infrequent event

BACKGROUND

Human papillomavirus (HPV) infection has been reported in squamous cell carcinomas of the oesophagus and has been recently described in Barrett's oesophagus, a premalignant condition which may give rise to oesophageal adenocarcinoma.

OBJECTIVES

To investigate HPV infection in Barrett's oesophagus in a UK population.

STUDY DESIGN

DNA was extracted from 73 Barrett's oesophagus biopsies and examined for the presence of DNA for 14 high risk (HR) and 6 low risk (LR) HPV types.

RESULTS

HPV DNA was present in only 1 of 73 samples; genotyping indicated this was a high risk type 51 infection.

CONCLUSIONS

HPV infection appears unlikely to be a significant factor in the aetiology of Barrett's oesophagus in the UK.

Prognostic value of cell adhesion in esophageal adenocarcinomas

Increased understanding of the molecular processes associated with the dysplasia-adenocarcinoma sequence linked to Barrett's esophagus may be beneficial for early tumor detection and refined diagnosis as well as for improved prognostication. We applied immunohistochemical staining for the markers Ki-67, p53, beta-catenin and E-cadherin in order to evaluate their prognostic importance in 59 Barrett's esophagus-associated adenocarcinomas. Reduced or absent membranous E-cadherin staining was identified in 75% of the tumors and predicted poor prognosis in manova (hazard ratio [HR] 3.3, P = 0.05). The small subset of tumors with low levels (< 10%) of Ki-67 staining showed a worse prognosis (HR 3.2, P < 0.01), whereas immunostaining for p53 and beta-catenin showed no correlation with prognosis. Deranged cell adhesion has been demonstrated to be an early event in tumor development. The down-regulation of E-cadherin and its prognostic importance indicate that cell adhesion may be a prime area for targeted therapies in esophageal adenocarcinoma.

Stepwise radical endoscopic resection of the complete Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities

OBJECTIVES

Malignant transformation of Barrett's mucosa is associated with the accumulation of genetic alterations. Stepwise radical endoscopic resection of the Barrett's segment with early neoplasia is a promising new treatment resulting in complete re-epithelialization of the esophagus with neosquamous epithelium. It is unknown whether radical resection also eradicates genetic abnormalities. The aim of this study was to prospectively evaluate whether genetic abnormalities as found in the Barrett's segment before radical resection are effectively eradicated and absent in the neosquamous epithelium.

METHODS

Nine patients with early neoplasia who successfully underwent radical resection were included. Immunohistochemistry (IHC) was performed to assess p53 protein overexpression. DNA fluorescent in-situ hybridization was (DNA-FISH) performed for evaluation of numerical abnormalities of chromosomes 1 and 9, and losses of p16 and p53. Immunohistochemistry and DNA-FISH were performed on endoscopic resection specimens of the neoplasia and on follow-up biopsies of the neosquamous epithelium.

RESULTS

DNA-FISH and IHC showed alterations in the pretreatment samples of all patients. All showed aneusomy of chromosome 1 and 9. Loss of p16 and p53 were seen in 6 and 8 patients. IHC showed intense p53 nuclear staining in seven patients. Post-treatment biopsies showed neosquamous epithelium with a normal diploid signal count for all DNA-FISH probes and normal IHC stainings in all patients.

CONCLUSIONS

Radical resection of Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities and results in neosquamous epithelium without these genetic abnormalities.

Bone morphogenic factor gene dosage abnormalities in prostatic intraepithelial neoplasia and prostate cancer

Abnormal expression of bone morphogenic proteins (BMP) has been reported in prostate cancer as compared to benign prostatic tissue. Since aberrations in gene expression often result from alterations in gene copy number, we have investigated this possibility in patients with early prostate cancer. Probes for fluorescence in situ hybridization for the BMP, BMP5, BMP7, and UC28 gene loci were developed and applied to archival sections with areas of adjacent benign epithelium, high-grade prostatic intraepithelial neoplasia, and prostate carcinoma. Two hundred nuclei from each region were evaluated. No deletions of the gene loci examined were observed, but gain of BMP2, BMP5, BMP7, and UC28 occurred in 58, 50, 50, and 67% of tumor foci, respectively. These aberrations in copy number may be caused by early events in tumor development because they were also present in 10-30% of high-grade prostatic intraepithelial hyperplasia foci. In addition, one tumor demonstrated a tandem amplification of the UC28 gene locus. Approximately half of the prostate tumors displayed increased copy numbers of the BMP2, BMP5, BMP7, and UC28 gene loci, which may account for their abnormal gene expression patterns in neoplastic prostate tissue.

Epithelial metaplasia and the development of cancer

Metaplasia means the conversion, in postnatal life, of one cell type to another. Understanding the steps leading to metaplasia is important for two reasons. Firstly, it tells us something about the normal developmental biology of the tissues that interconvert. Secondly, metaplasia predisposes to certain forms of neoplasia. So understanding the molecular and cellular mechanisms underlying metaplasia will provide insights into clinical diagnosis and potential therapies. One of the best-described examples of metaplasia is Barrett's metaplasia or the appearance of intestinal-like columnar tissue in the oesophagus. Barrett's metaplasia develops as a result of gastro-oesophageal reflux and is considered the precursor lesion for oesophageal adenocarcinoma. While we know quite a bit about the molecular events associated with the development of oesophageal adenocarcinoma, our understanding of the initial events leading to Barrett's metaplasia is lacking. In the present review we will focus on examples of metaplasia that lead to neoplasia and discuss some of the underlying molecular and cellular mechanisms.

Analysis of R213R and 13494 g-->a polymorphisms of the p53 gene in individuals with esophagitis, intestinal metaplasia of the cardia and Barrett's Esophagus compared with a control group

Protein p53 is the tumor suppressor involved in cell cycle control and apoptosis. There are several polymorphisms reported for p53 which can affect important regions involved in protein tumor suppressor activity. Amongst the polymorphisms described, R213R and 13949 g-->a are rarely studied, with an estimate frequency not yet available for the Brazilian population. The purpose of this study was to investigate the genotype and allele frequencies and associations of these polymorphisms in a group of patients with altered esophageal tissue from South Brazil and compare with the frequency observed for a control population. A total of 35 patients for R213R and 45 for 13494 g-->a polymorphisms analysis with gastroesophageal reflux disease (GERD) symptoms diagnosed by upper digestive endoscopy and confirmed by biopsy were studied. For both groups, 100 controls were used for comparison. Loss of heterozygosity (LOH) was also analyzed for a selected group of patients where normal and affected tissue was available. There was one patient with Barrett's Esophagus (BE) showing LOH for R213R out of two heterozygous samples analyzed and two patients (esophagitis and BE) for 13494 g-->a polymorphism. We also aimed to build a haplotype for both polymorphisms collectively analyzed with R27P polymorphism, previously reported by our group. There were no significant differences in allele and genotype distribution between patients and controls. Although using esophagitis, intestinal metaplasia of the cardia and BE samples, all non-neoplastic lesions, we can conclude that these sites do not represent genetic susceptibility markers for the development and early progression of GERD to BE and esophageal cancer. Additional studies are required in order to investigate other determiners of early premalignant lesions known to predispose to esophageal cancer.

Clinical use of p53 in Barrett's esophagus

Barrett's esophagus is an established precursor to esophageal adenocarcinoma. Whereas most patients with Barrett's esophagus do not progress to adenocarcinoma, patients with progression have a poor prognosis. Current management strategies use frequent endoscopic surveillance and multiple nontargeted biopsies. This approach, however, may miss dysplastic areas. Furthermore, given the relatively high prevalence of Barrett's esophagus but low incidence of progression, this invasive and expensive approach has not been shown to be cost-effective. Thus, there is intense interest in using biomarkers to identify patients at increased risk of progressing to adenocarcinoma. This has included examination of mutations in the tumor suppressor gene, p53. In this report, we discuss the biology of p53 and the incidence of p53 mutations in Barrett's esophagus and review relevant studies regarding the ability of p53 to predict neoplastic progression. Additionally, we report our results of the expression of p53 by immunohistochemistry in a group of 18 patients that have undergone endoscopic esophageal mucosal resection for dysplasia. Although the presence of a p53 mutation increases the risk of neoplastic progression, the absence of this mutation does not abrogate the risk. Continuing efforts, therefore, are needed to define and prospectively validate a panel of biomarkers to risk-stratify patients with Barrett's esophagus. Determination of p53 mutational status may ultimately be a component of such a panel.

Raman spectroscopy: elucidation of biochemical changes in carcinogenesis of oesophagus

Several techniques are under development to diagnose oesophageal adenocarcinoma at an earlier stage. We have demonstrated the potential of Raman spectroscopy, an optical diagnostic technique, for the identification and classification of malignant changes. However, there is no clear recognition of the biochemical changes that distinguish between the different stages of disease. Our aim is to understand these changes through Raman mapping studies. Raman spectral mapping was used to analyse 20-microm sections of tissue from 29 snap-frozen oesophageal biopsies. Contiguous haematoxylin and eosin sections were reviewed by a consultant pathologist. Principal component analysis was used to identify the major differences between the spectra across each map. Pseudocolour score maps were generated and the peaks of corresponding loads identified enabling visualisation of the biochemical changes associated with malignancy. Changes were noted in the distribution of DNA, glycogen, lipids and proteins. The mean spectra obtained from selected regions demonstrate increased levels of glycogen in the squamous area compared with increased DNA levels in the abnormal region. Raman spectroscopy is a highly sensitive and specific technique for demonstration of biochemical changes in the carcinogenesis of Barrett's oesophagus. There is potential for in vivo application for real-time endoscopic optical diagnosis.

Loss of heterozygosity of chromosome 3p21 is associated with mutant TP53 and better patient survival in non-small-cell lung cancer

Allelic loss of chromosome region 3p21.3 occurs early and frequently in non-small-cell lung cancer, and numerous tumor suppressor genes at this locus may be targets of inactivation. Using an incident case series study of non-small-cell lung cancer, we sought to determine the prevalence of loss of heterozygosity (LOH) in the 3p21.3 region and to examine the associations between this alteration and patient outcome, exposure to tobacco smoke, occupational asbestos exposure, and additional molecular alterations in these tumors. We examined LOH at 7 microsatellite markers in the chromosome 3p21.3 region, and LOH was present in at least one of the loci examined in 60% (156 of 258) of the tumors, with the prevalence of LOH at individual loci ranging from 15 to 56%. Occupational asbestos exposure and TP53 mutation were significantly associated with more extensive 3p21 LOH. In squamous cell carcinomas, measures of cumulative smoking dose were significantly lower in patients with LOH at 3p21, particularly in TP53 mutant tumors. Examining patient outcome, we found that in squamous cell carcinomas, having any LOH in this region was associated with a better overall survival (log-rank test, P < 0.04). Together, these results indicate that allelic loss at 3p21 can affect patient outcome, and that this loss may initially be related to carcinogen exposure, but that extension of this loss is related to TP53 mutation status and occupational asbestos exposure.

The molecular biology of esophageal adenocarcinoma

BACKGROUND

Barrett's esophagus is an acquired metaplastic change that occurs in the distal esophagus secondary to chronic gastroesophageal reflux. This premalignant condition forms the most important risk factor for developing esophageal adenocarcinoma, which is an extremely aggressive tumor with a 5-year survival rate of less than 25%. Carcinomas that arise in the setting of Barrett's esophagus are thought to develop as part of the metaplasia-dysplasia-carcinoma sequence.

OBJECTIVE

To review the current knowledge on the genomic alterations involved in the development of Barrett's esophagus and its progression to dysplasia and/or cancer.

RESULTS

Several changes in gene structure, gene expression, and protein structure are associated with the progression of Barrett's esophagus to adenocarcinoma. Accumulation of these changes seems to be essential, rather than the exact sequence of these changes. Multiple molecular pathways are involved and interact with each other. Alterations in tumor suppressor genes, amongst which p53 and p16, are early events in the metaplasia-dysplasia-adenocarcinoma sequence, followed by loss of cell cycle checkpoints. Ongoing genomic instability leads to cumulative genetic errors and thereby the generation of multiple clones of transformed cells.

CONCLUSIONS

Within the multistep process of esophageal adenocarcinogenesis, to date no single molecular marker came forward able to predict who will and who will not develop cancer in the setting of Barrett's esophagus. Instead, panels of markers need to be developed in the future allowing to indicate disease progression. Identification of crucial molecular pathways involved in esophageal adenocarcinogenesis would ultimately improve therapy and facilitate development of new treatment strategies.

Molecular alterations during development of esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma has risen significantly over the last decades. During esophageal carcinogenesis many molecular alterations occur that disrupt essential cellular processes, directing the cell to a rapidly proliferating, immortal state. The chronic inflammation that is present in Barrett's esophagus creates an environment in which such molecular alterations are both induced and tolerated. Here, the novel insights in the molecular mechanisms that underlie the development of esophageal adenocarcinoma are reviewed, focusing on the role of inflammation, angiogenesis, apoptosis inhibition, loss of cell cycle control, and loss of cell-cell adhesion. These novel developments will open new perspectives for diagnosis, treatment, and prevention of esophageal adenocarcinoma.

Peptide YY inhibits the growth of Barrett's esophageal adenocarcinoma in vitro

BACKGROUND

Peptide YY (PYY) is an endogenous gut hormone that inhibits the growth of certain cancers. Adenocarcinoma of the esophagus usually arises from Barrett's esophagus. We hypothesized that treatment of Barrett's adenocarcinoma with PYY would result in decreased proliferation.

METHODS

Barrett's cancer cell lines (BIC and SEG-1) were treated with PYY (3-36) at 500 pmol/mL. Viability was measured by MTT at 24 and 72 hours. Apoptosis and necrosis was evaluated by flow cytometry.

RESULTS

PYY reduced proliferation in SEG-1 cells at 24 hours (21.2% +/- 3.4%, P <0.001) and 72 hours (14.2% +/- 6.2%, P <0.001). In the BIC cells, growth was inhibited by 7.9% +/- 7.0%, P = 0.021 after 72 hours. PYY increased late apoptotic activity in SEG-1 cells by 31%, P = 0.014.

CONCLUSIONS

This is the first report of antiproliferative effects of PYY against Barrett's carcinoma in vitro. Reductions in cell growth appear to be mediated by proapoptotic mechanisms. Further investigation of PYY in the treatment of Barrett's adenocarcinoma is warranted.

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A population-based study of immunohistochemical detection of p53 alteration in bladder cancer

The molecular pathology of bladder cancer has been the subject of considerable interest and mutation of the p53 gene, which has been associated with more invasive bladder cancer, has been widely studied. Further, there is evidence that p53 inactivation (either mutation or protein dysregulation), independent of stage, may be predictive of bladder cancer progression. In an effort to avoid possible biases associated with selection of more advanced cases, we examined p53 inactivation in a population-based study of bladder cancer in New Hampshire, using both mutation and immunohistochemical methods. We found the overall prevalence of mutation to be approximately 10%, while immunohistochemical analysis suggests that approximately 66% of the tumours have dysregulated p53 at the protein level. There was a significant association of mutation with persistent p53 staining, but there remained a marked number of tumours discordant for mutation and aberrant p53 immunohistochemistry. Based upon immunohistochemical staining alone, intensity rather than extent of p53 staining was more strongly related to tumour invasiveness. Additionally, all tumours with a mutation in exon 8 stained intensely. Taken together, this suggests that intense staining represents a distinct phenotype of dysfunctional protein. Our data indicate that population-based approaches to somatic alteration of p53 in bladder cancer are crucial to understanding the relationship of p53 changes to aetiology and the outcome of this disease, and further suggest that the pattern of immunohistochemical staining may represent distinct, discernible phenotypes.