Molecular biology of Barrett's adenocarcinoma.

Objective: To review the current knowledge on the genetic alterations involved in the development and progression of Barrett's esophagus-associated neoplastic lesions.

Summary Background Data: Barrett's esophagus (BE) is a premalignant condition in which the normal squamous epithelium of the esophagus is replaced by metaplastic columnar epithelium. BE predisposes patients to the development of esophageal adenocarcinoma.

Absence of a PDX-1 mutation and normal gastroduodenal immunohistology in a child with pancreatic agenesis.

Pancreatic agenesis is a rare condition, of which only a limited number of cases have been described. One recent paper reported a homozygous mutation in the pancreatic duodenal homeobox gene 1 (PDX-1) in a child with pancreatic agenesis. We report a 6-year-old boy with pancreatic agenesis, treated medically, without abnormalities in the PDX-1 gene coding sequence and with normal gastroduodenal endocrine cell distribution.

Losses of chromosomes 1p and 3q are early genetic events in the development of sporadic pheochromocytomas.

Despite several loss of heterozygosity studies, a comprehensive genomic survey of pheochromocytomas is still lacking. To identify DNA copy number changes which might be important in tumor development and progression and which may have diagnostic utility, we evaluated genetic aberrations in 29 sporadic adrenal and extra-adrenal pheochromocytomas (19 clinically benign tumors and 10 malignant lesions). Comparative genomic hybridization was performed using directly fluorochrome-conjugated DNA extracted from frozen (16) and paraffin-embedded (13) tumor tissues.

E-cadherin-catenin cell-cell adhesion complex and human cancer.

Background: The E-cadherin-catenin complex plays a crucial role in epithelial cell-cell adhesion and in the maintenance of tissue architecture. Perturbation in the expression or function of this complex results in loss of intercellular adhesion, with possible consequent cell transformation and tumour progression. Recently, much progress has been made in understanding the interaction between the different components of this protein complex and how this cell-cell adhesion complex is modulated in cancer cells.

RET is expressed but not mutated in extra-adrenal paragangliomas.

This study has investigated the role of the RET proto-oncogene, which has been identified as the susceptibility gene for multiple endocrine neoplasia (MEN) type 2, in the development of sporadic and familial extra-adrenal paragangliomas. RET protein expression was analysed by immunohistochemistry. Subsequently, DNA extracted from 52 tumours of 44 patients was screened for somatic RET point mutations in exons 10, 11, and 13-16, where oncogenic mutations have recently been described in a subset of sporadic medullary thyroid carcinomas and phaeochromocytomas.

Proliferative index in phaeochromocytomas: does it predict the occurrence of metastases?

Evaluation of the malignant potential of phaeochromocytomas in the absence of metastases presents a formidable challenge to both clinicians and pathologists. Until now, no widely accepted clinical, histological, immunohistochemical or molecular method has become available to discriminate malignant from benign phaeochromocytomas. In other endocrine tumours, estimation of proliferative activity by MIB-1 immunostaining has emerged as a promising approach for the determination of metastatic potential.

Genetic alterations involving exon 3 of the beta-catenin gene do not play a role in adenocarcinomas of the esophagus.

Beta-catenin has been identified as an oncogene. Phosphorylation of sites encoded by exon 3 of the beta-catenin gene facilitates degradation of this protein by the adenomatous polyposis coli (apc) gene product. Mutations in these sites or inactivation of apc lead to stabilization of beta-catenin, which then translocates to the nucleus where it modulates the transcription of genes involved in tumor formation.

Human oesophageal adenocarcinoma cell lines JROECL 47 and JROECL 50 are admixtures of the human colon carcinoma cell line HCT 116.

In two recently described human oesophageal adenocarcinoma cell lines JROECL 47 and JROECL 50, derived from one tumour, we detected identical E-cadherin and beta-catenin gene mutations as in colon carcinoma cell line HCT 116. We demonstrate by HLA-typing, mutation analysis and microsatellite analysis that cell lines JROECL 47 and JROECL 50 are admixtures of the human colon adenocarcinoma cell line HCT 116.

E-cadherin promotes intraepithelial expansion of bladder carcinoma cells in an in vitro model of carcinoma in situ.

High-grade transitional cell carcinomas (TCCs) of the urinary bladder are frequently associated with carcinoma in situ, which may replace large areas of the mucosa of the urinary tract. The invasive component of TCCs often reveals a loss of expression of the cell-cell adhesion molecule E-cadherin, but the role of E-cadherin in the development and expansion of intraepithelial neoplasia is unknown. To study the underlying mechanism of intraepithelial expansion (IEE), we have developed an IEE assay.

A comparative evaluation of various invasion assays testing colon carcinoma cell lines.

Various colon carcinoma cell lines were tested in different invasion assays, i.e. invasion into Matrigel, into confluent fibroblast layers and into chicken heart tissue.

E-cadherin gene mutations are rare in adenocarcinomas of the oesophagus.

Reduced expression of E-cadherin, a cell-cell adhesion molecule, is observed in oesophageal adenocarcinomas and correlates with less favourable pathological parameters and survival. To determine if genetic events lead to reduced E-cadherin expression in these patients, we screened all 16 exons of the E-cadherin gene for mutations with the polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) technique in 49 resection specimens, including four loco-regional lymph node metastases, four established cell lines and four xenografts. Fifteen exon-spanning primer pairs were used, and in nine amplicons aberrant bands were detected.

Prognostic value of p53, bcl-2, and c-erbB-2 protein expression in phaeochromocytomas.

Many studies have tried to discriminate malignant from benign phaeochromocytomas, but until now no widely accepted histological, immunohistochemical, or molecular methods have been available. In this study of 29 malignant and 85 benign phaeochromocytomas from 102 patients, immunohistochemistry was performed with antibodies to the tumour suppressor gene product p53 and the proto-oncogene products bcl-2 and c-erbB-2, using the avidin-biotin complex method. Malignant phaeochromocytomas showed a statistically significant higher frequency of p53 (p=0.

Molecular assessment of clonality leads to the identification of a new germ line TP53 mutation associated with malignant cystosarcoma phyllodes and soft tissue sarcoma.

Cystosarcoma phyllodes (CSP) is a rare breast neoplasm composed of stromal and epithelial elements. It usually runs a benign course but it may metastasize. In a 31-year-old patient with recurring CSP, a mesenchymal tumor in the leg developed.

Comparative genomic hybridization of cancer of the gastroesophageal junction: deletion of 14Q31-32.1 discriminates between esophageal (Barrett's) and gastric cardia adenocarcinomas.

Incidence rates have risen rapidly for esophageal and gastric cardia adenocarcinomas. These cancers, arising at and around the gastroesophageal junction (GEJ), share a poor prognosis. In contrast, there is no consensus with respect to clinical staging resulting in possible adverse effects on treatment and survival.

Identification of a homozygous deletion at 8p12-21 in a human prostate cancer xenograft.

One of the most frequent genetic abnormalities in prostate cancer is loss of the complete or part of the short arm of chromosome 8, indicating the localization of one or more tumor suppressor genes on this chromosomal arm. Using allelotyping, a frequently deleted region in prostate cancer in a genetic interval of approximately 17 cM between sequence tagged sites D8S87 and D8S133 at chromosome arm 8p12-21 was previously detected. A detailed physical map of this region is now available.

Expression of differentiation-related genes in colorectal cancer: possible implications for prognosis.

Although differentiation grade is an important prognostic factor for colorectal tumors, its usefulness is limited since its predictive value for tumor behavior is not very significant. This might be related to the subjective nature of histological assessment of differentiation grade, which allows the distinction of only three grades, and with limited reproducibility. Characterization of the differentiation process at the biochemical level may improve our understanding of normal and malignant differentiation, and is expected to provide molecular markers with higher discriminative potential than histomorphology.

Germline mutations in the vhl gene in patients presenting with phaeochromocytomas.

It has been shown that an appreciable percentage of patients presenting with primary, apparently sporadic phaeochromocytomas may in fact have von-Hippel-Lindau (VHL) disease. In order to investigate this, we retrospectively screened 68 patients, who had been operated on for phaeochromocytomas, for the presence of germline mutations in the vhl gene. DNA was isolated from peripheral-blood leukocytes and used to screen the entire coding sequence and the intron-exon boundaries of the vhl gene for mutations, using a PCR-based SSCP strategy.

Expression of a marker for colonic crypt base cells is correlated with poor prognosis in human colorectal cancer.

Background: There is a need for markers in colorectal cancer which will allow subclassification of stage groups into subgroups with high versus low risk of recurrent disease.

Aims: To develop monoclonal antibodies that recognise antigens or immature crypt base cells, on the assumption that in a neoplasm undifferentiated but not the terminally differentiated cells will be responsible for tumour progression.

Methods: Colon crypt cells which were isolated from human colonic mucosa by EDTA/EGTA incubation were studied.

Clonal growth of colorectal-carcinoma cell lines transplanted to nude mice.

It is generally assumed that tumor progression is a microevolutionary process in which increasingly aggressive clones, generated through genetic instability, emerge in an initially monoclonal lesion. The present study was undertaken to determine how rapidly a dominant clone will emerge from an initial polyclonal situation, and whether dominance of these clones is a prerequisite for the onset of metastasis. To this end, colon-carcinoma cells were infected in culture with an amphotropic retroviral vector containing the neomycin-phosphotransferase gene, which makes cells resistant to neomycin.

Proliferation and apoptosis in proliferative lesions of the colon and rectum.

Classically, neoplasia has been considered to be primarily a disturbance in the regulation of proliferation, but it is now clear that programmed cell death is dysregulated as well as proliferation. The genes that are implicated in the regulation of these processes, such as p53, c-myc and bcl-2, are often also altered in neoplasms. We have studied proliferation and programmed cell death in hyperplastic polyps, adenomas, carcinomas in adenomas and adenocarcinomas of the colorectum, using the MIB-1 antibody which recognizes the Ki-67 proliferation related antigen, and an in situ nick-end labelling procedure for histochemical labelling of proliferating and apoptotic cells.

Reduced expression of the cadherin-catenin complex in oesophageal adenocarcinoma correlates with poor prognosis.

The E-cadherin-catenin complex is important for cell-cell adhesion of epithelial cells. Impairment of one or more components of this complex is associated with poor differentiation and increased invasiveness of carcinomas. Oesophageal adenocarcinomas causes early metastases, progress rapidly, and consequently have a poor prognosis.

A novel gene which is up-regulated during colon epithelial cell differentiation and down-regulated in colorectal neoplasms.

To identify new molecular markers for differentiation of normal and neoplastic colon epithelium, we have studied changes in gene expression during the in vitro differentiation of the HT29-D4 colon carcinoma cell line. Using a modified differential display procedure, we cloned a novel cDNA, designated differentiation-related gene 1 (Drg1). Drg1 mRNA has a length of approximately 3 kb and is induced approximately 20-fold during in vitro differentiation of the colon carcinoma cell lines HT29-D4 and Caco-2.

A new monoclonal antibody for specific immunocytochemical staining of nucleoli.

We have isolated a hybridoma cell line (clone 1E10) producing a monoclonal antibody which specifically recognizes nucleoli. The antibody (IgM, k isotype) was found to react in a nucleolar pattern with a variety of cell types. Specific staining was only obtained on cryostat sections of unfixed tissues.

Expression of nucleophosmin/B23 in normal and neoplastic colorectal mucosa.

Nucleophosmin/B23 is a 38 kD molecular phosphoprotein involved in ribosome assembly and transport. In view of the fact that nucleophosmin/B23 appears to be more abundant in tumour cells than in normal cells, the mRNA expression and immunohistochemical localization of nucleophosmin/B23 were investigated in 19 samples of non-neoplastic mucosa, six adenomas, and 16 adenocarcinomas of the colorectum. Northern blot analysis revealed that nucleophosmin/B23 mRNA is expressed at a higher level in adenomas and carcinomas than in non-neoplastic mucosa of the colorectum.