[Epigenetic changes in the promoter of the fragile histidine triad (FHIT) gene in human sebocytes under the influence of in vitro culture].

Background: Due to the lack of tumor suppressor function of the fragile histidine triad (FHIT) gene product, sebaceous gland carcinomas can develop.

Objective: The model of the sebocyte cell line SZ95 was used to identify methylated CpG islands at the 5'-end of the FHIT gene and the decrease of gene expression as well as the increase of double-stranded (ds) DNA breaks were examined.

Material And Methods: Methylation, immunofluorescence analysis, promotor sequencing and treatment of SZ95 cells with 5‑azacytidine/trichostatin A (TSA).

Identification of lymphocyte cell-specific protein-tyrosine kinase (LCK) as a driver for invasion and migration of oral cancer by tumor heterogeneity exploitation.

Background: Cancer metastases are the main cause of lethality. The five-year survival rate for patients diagnosed with advanced stage oral cancer is 30%. Hence, the identification of novel therapeutic targets is an urgent need.

Deletions of BRCA1/2 and p53 R248W gain-of-function mutation suggest impaired homologous recombination repair in fragile histidine triad-negative sebaceous gland carcinomas.

Background: Sebaceous gland carcinomas represent rare malignancies of the skin and some 60% of them demonstrate high-grade microsatellite instability on the background of a defective mismatch repair system. However, a significant fraction of periocular sebaceous gland carcinomas exhibits microsatellite stability associated with a frequent loss of the candidate tumour suppressor fragile histidine triad (FHIT).

Objectives: We hypothesized that in those sebaceous gland carcinomas with microsatellite stability and loss of FHIT, effector molecules participating in homologous recombination repair (HRR), such as BRCA1/2, could be somatically inactivated.

Epigenetic silencing contributes to frequent loss of the fragile histidine triad tumour suppressor in basal cell carcinomas.

Background: Extensive exposure to ultraviolet radiation is associated with genetic alterations in basal cell carcinomas (BCCs), which represent some 75% of skin cancers.

Objectives: As recent data suggested the fragile histidine triad (FHIT) gene product to participate in DNA damage responses we wished to address whether functional deletion of this tumour suppressor participates in the development of BCC. Our study focused on epigenetic inactivation of the FHIT gene.

Prospero-related homeobox 1 (PROX1) is frequently inactivated by genomic deletions and epigenetic silencing in carcinomas of the bilary system.

Background/aims: Functional deletion of the transcription factor Prospero-related homeobox 1 (PROX1) causes abnormal cellular proliferation via down-regulated expression of the cell cycle inhibitors p27(kip1) and p57(kip2). Hence, we examined whether inactivation of the PROX1 gene can be demonstrated in malignant tumors of the bilary system.

Methods: Seventeen paraffin-embedded specimens of carcinomas of the bilary system were subjected to loss-of-heterozygosity (LOH) and microsatellite instability analyses, methylation-specific polymerase-chain reaction (MSP) and immunohistochemical detection of PROX1 protein in tumor sections.

Different genetic pathways in the development of periocular sebaceous gland carcinomas in presumptive Muir-Torre syndrome patients.

Periocular sebaceous gland carcinomas (SGCs) occur in the eyelids either sporadically or as a phenotypic feature of Muir-Torre syndrome (MTS). In knockout mice mismatch-repair (MMR) defects or inactivation of the fragile histidine triad (FHIT) gene are associated with MTS-like signs, including SGC. To dissect the genetic alterations associated with microsatellite instability (MSI) and inactivation of the FHIT gene, we studied nine periocular SGC specimens from MTS patients.

Promoter methylation and loss of coding exons of the fragile histidine triad (FHIT) gene in intrahepatic cholangiocarcinomas.

Aims: About 10-30% of primary liver cancers represent intrahepatic cholangiocarcinomas (IHCC). Since chromosomal losses of 3p are detectable in about 40% of cholangiocarcinomas our study aimed at the identification of mechanisms leading to functional deletion of tumor suppressor genes in this region. Our efforts focussed on genomic losses and epigenetic inactivation of two tumor suppressor genes, the fragile histidine triad (FHIT) and the ras association domain family 1 (RASSF1A) genes, both located on the short arm of chromosome 3.

Forced expression of deltaN-TCF-1B in colon cancer derived cell lines is accompanied by the induction of CEACAM5/6 and mesothelin.

The colon cancer cell lines HT29 and SW480 were transfected with an N-terminal beta-catenin binding site-deficient high mobility group (HMG)-box T-cell factor 1 (deltaN-TCF-1) construct to identify differentially expressed genes. Oligonucleotide HG-U133A microarray expression profiling revealed increased mRNA levels of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 5, 6 and mesothelin in transfectants positive for nuclear deltaN-TCF-1B. Increased amounts of CEACAM5 (CEA) were detectable in membrane-associated compartments, particularly in cholesterol-enriched microdomains.

Genetic testing for germline mutations of the APC gene in patients with apparently sporadic desmoid tumors but a family history of colorectal carcinoma.

Purpose: Desmoid tumors, also known as aggressive fibromatosis, occur with an incidence of 10 to 15 percent in patients affected by familial adenomatous polyposis, an autosomal inherited disease caused by germline mutations in the APC gene. However, sporadic forms with no hereditary background exist. The aim of this study was to find out whether there are APC germline mutations in apparently sporadic desmoid tumor patients without clinical or familial signs of familial adenomatous polyposis but with a family history of colorectal carcinoma in at least one family member.

Frequency and clinical features of visceral malignancy in a consecutive case series of patients with periocular sebaceous gland carcinoma.

Purpose: To report the frequency and clinical features of internal visceral malignancy in an unselected series of patients with sebaceous gland carcinoma (SGC).

Methods: A non-comparative retrospective case series of consecutive patients with a histologically proven diagnosis of periocular sebaceous cell carcinoma treated at the University Eye Hospital, University of Erlangen-Nürnberg between 1981 and 2000.

Results: Twenty-three patients were identified, each with one tumor.

Genetic screening for Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome is clinically characterized by mucocutaneous melanocytic pigmentation, intestinal hamartomatous polyposis and a significantly increased risk of developing cancer. Mutations in the serine/threonine kinase (STK-)11 gene, also designated LKB1, are found in approximately 60% of cases of Peutz-Jeghers syndrome. There is evidence that genetic heterogeneity exists and gene(s) that have not yet been discovered may be responsible for the disease.

Alteration of the fragile histidine triad gene in intrahepatic cholangiocarcinoma.

Background And Aims: Intrahepatic cholangiocarcinoma is the second most common intrahepatic neoplasm, accounting for 10-30% of primary liver cancers. Since little is known about the development of this cancer, we searched for alterations to the fragile histidine triad (FHIT) gene, a putative tumour suppressor gene on chromosome 3p14.2.

Loss of fragile histidine triad (FHIT) expression and microsatellite instability in periocular sebaceous gland carcinoma in patients with Muir-Torre syndrome.

Purpose: To report fragile histidine triad expression and microsatellite instability in periocular sebaceous gland carcinoma.

Design: Interventional case series.

Methods: Biopsy specimens of periocular sebaceous gland carcinoma obtained from six patients (mean age, 60 +/- 17 years; range, 38 to 83 years, 5 male, 1 female) with Muir-Torre syndrome and histopathologically proven sebaceous gland carcinoma were studied immunohistochemically for the presence of fragile histidine triad protein.

Mutation screening at the RNA level of the STK11/LKB1 gene in Peutz-Jeghers syndrome reveals complex splicing abnormalities and a novel mRNA isoform (STK11 c.597(insertion mark)598insIVS4).

This study was intended to evaluate a diagnostic reverse transcriptase polymerase chain reaction based protein-truncation test for the identification of germline mutations in the serine/threonine protein kinase 11 (STK11, also designated LKB1) gene in Peutz-Jeghers syndrome (PJS). Our data exemplify that the inactivation of STK11 can be due to unusual disturbances in splicing regulation which result in truncations of the protein. However, nonsense mediated mRNA decay must be blocked with puromycin to detect shortened STK11 gene products contained in the leucocytic mRNA pool of PJS patients.

Multiple primary malignancies: An epidemiological and pedigree analysis of 57 patients with at least three tumours.

Aim And Methods: Data of our patients with at least three primary malignancies were retrospectively analysed to detect any remarkable patterns which might be of interest for follow-up or early tumour detection and to identify a possible hereditary cancer predisposition. From 1.1.

DHPLC mutation analysis of the hereditary nonpolyposis colon cancer (HNPCC) genes hMLH1 and hMSH2.

Denaturing high-performance liquid chromatography (DHPLC) is an efficient method for detection of mutations involving a single or few numbers of nucleotides, and it has been successfully used for mutation detection in disease-related genes. Colorectal cancer is one of the most common cancers, and mutations in the genes for hereditary nonpolyposis colon cancer (HNPCC), hMLH1 and hMSH2, also involve mainly point mutations. Sequence analysis is supposed to be a screening method with high sensitivity; however, it is time-consuming and expensive.

Three novel types of splicing aberrations in the tuberous sclerosis TSC2 gene caused by mutations apart from splice consensus sequences.

Disease causing aberrations in both tuberous sclerosis predisposing genes, TSC1 and TSC2, comprise nearly every type of alteration with a predominance of small truncating mutations distributed over both genes. We performed an RNA based screening of the entire coding regions of both TSC genes applying the protein truncation test (PTT) and identified a high proportion of unusual splicing abnormalities affecting the TSC2 gene. Two cases exhibited different splice acceptor mutations in intron 9 (IVS9-15G-->A and IVS9-3C-->G) both accompanied by exon 10 skipping and simultaneous usage of a cryptic splice acceptor in exon 10.

Genetic testing for familial adenomatous polyposis.

Familial adenomatous polyposis (FAP, Mendelian Inheritance in Man number *175,100 [edited by Victor A. McKusick], accessible on line under http:¿www3.ncbi.

RNA-based mutation screening in German families with Sjögren-Larsson syndrome.

Sjögren-Larsson syndrome (SLS) is a rare autosomal recessively inherited disorder characterised by mental retardation, spasticity and ichthyosis. SLS patients have a profound deficiency in fatty aldehyde dehydrogenase (FALDH) activity. The human cDNA of FALDH has been shown to map to the SLS locus on chromosome 17p11.

[Hereditary colonic carcinoma without polyposis (HNPCC) without satisfying the Amsterdam criteria].

Epidemiologic data suggest that an underlying genetic disposition can be detected in up to 10% of all colorectal cancer patients and autosomal dominantly inherited hereditary non-polyposis colorectal cancer (HNPCC) is the entity most frequently identified. It was described first by A. Warthin in 1895 in "Family G" and is characterized by a predisposition to an early onset of colorectal cancer and other intestinal or genitourinary tumors.

A proven de novo germline mutation in HNPCC.

Hereditary non-polyposis colon cancer (HNPCC) is a heterogeneous group of tumour predisposition syndromes caused by germline mutations in at least four different mismatch repair genes. HNPCC patients are prone to the development of carcinomas of the intestinal tract and other specific sites. Identification of presumptive HNPCC patients is primarily based on a positive family history of colorectal cancer in at least two generations.

Mutation screening of the entire coding regions of the TSC1 and the TSC2 gene with the protein truncation test (PTT) identifies frequent splicing defects.

Mutation analyses in tuberous sclerosis (TSC) have reported a wide variety of disease-causing aberrations in the two known predisposing genes, TSC1 and TSC2 on chromosomes 9q34 and 16p13, comprising mainly small mutations distributed over the entire genes. So far, all known TSC1 mutations as well as the majority of TSC2 mutations truncate the proteins hamartin and tuberin, respectively. We describe for the first time an RNA-based screening of the entire coding regions of both TSC genes for truncating mutations applying the protein truncation test (PTT).