Biomedical subjects

U Bergerheim

Publications and source records attributed to U Bergerheim.

10 recordsLinked to original sources

PubMed2002

Clinical and genetic studies of Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant cancer syndrome characterised by benign skin tumours, renal tumours, and spontaneous pneumothorax. The gene has been mapped to chromosome 17p11.2 and recently identified, expressing a novel protein called folliculin. We report the clinical and genetic studies of four sporadic BHD cases and four families with a total of 23 affected subjects. Haplotype analysis of these families using BHD linked markers showed they did not share the same affected alleles, excluding common ancestry. Mutation analysis of the BHD gene identified two germline mutations on exon 11 (c.1733insC and c.1733delC) in three of four families as well as two of four sporadic cases. A novel somatic mutation, c.1732delTCinsAC, was detected in a BHD related chromophobe renal carcinoma. Our results confirmed the (C)8 tract in exon 11 as a mutational hot spot in BHD and should always be considered for future genetic testing. Our observation also indicated that the second hit (of Knudson's two hit theory) in some BHD related tumours is in the form of somatic mutation rather than LOH. In a large French family in which eight affected subjects carry the c.1733delC mutation, a phenocopy who has multiple episodes of spontaneous pneumothorax was identified. A total of five mutation carriers (aged between 37 to 66) did not have any evidence of BHD features, suggesting either reduced penetrance or late age of onset of the disease. In addition, six out of eight affected subjects who have positive germline mutation have confirmed neoplastic colonic polyps, indicating that colorectal neoplasia is an associated feature of BHD in some families. Our studies have observed several interesting genetic features in BHD: (1) the poly (C) tract in exon 11 as a mutational hot spot; (2) the existence of phenocopy; (3) reduced penetrance or late age of onset of disease; (4) association with colorectal neoplasia in some families; and (5) somatic mutation instead of LOH as the second hit in BHD tumours.

Adult↗

PubMed2000

Combined LOH/CGH analysis proves the existence of interstitial 3p deletions in renal cell carcinoma.

We have recently developed an allele titration assay (ATA) to assess the sensitivity and influence of normal cell admixture in loss of heterozygosity (LOH) studies based on CA-repeat. The assay showed that these studies are biased by the size-dependent differential sensitivity of allele detection. Based on these data, we have set up new criteria for evaluation of LOH. By combining these new rules with comparative genome hybridization (CGH) we have shown the presence of interstitial deletions in renal cell carcinoma (RCC) biopsies and cell lines. At least three out of 11 analysed RCC cell lines and three out of 37 biopsies contain interstitial deletions on chromosome 3. Our study suggests the presence of several regions on human chromosome 3 that might contribute to tumor development by their loss: (i) 3p25-p26, around the VHL gene (D3S1317); (ii) 3p21. 3-p22 (between D3S1260 and D3S1611); (iii) 3p21.2 (around D3S1235 and D3S1289); (iv) 3p13-p14 (around D3S1312 and D3S1285). For the first time, AP20 region (3p21.3-p22) was carefully tested for LOH in RCC. It was found that the AP20 region is the most frequently affected area. Our data also suggest that another tumor suppressor gene is located near the VHL gene in 3p25-p26.

Alleles↗

PubMed2000

Chromosomal numerical aberrations detected by fluorescence in situ hybridization on bladder washings from patients with bladder cancer.

OBJECTIVE: Previous studies on touch biopsy specimens have determined numerical or structural changes involving many different chromosomes in bladder cancer. The aim of this study was to evaluate the use of fluorescence in situ hybridization (FISH) assay in bladder washings as an objective technique to detect chromosomal numerical aberrations in bladder cancer. The main advantages of bladder washings are that they can be easily collected during the clinical follow-up of patients with superficial bladder cancer and they do not contain so many degenerate cells as urine samples. METHODS: We collected specimens from 25 patients who underwent transurethral resection of bladder tumors. Double target FISH assays with centromeric labeled probes for chromosomes 7, 8, 9 and 11 were used on the bladder washings and on the touch biopsy slides. The results were compared to flow cytometry and tumor grade and stage. RESULTS: We found monosomy 9 and trisomy 7, 8, 9 and 11 in 28, 32, 36, 28 and 25% respectively of the patients. FISH analysis of bladder washing versus touch biopsy specimens were concordant in approximately 90% of the slides. Total DNA aneuploidy correlated well with numerical aberrations of chromosomes 7, 8 and 11, but not with chromosome 9. CONCLUSION: Although better hybridization efficiency was obtained on touch biopsy slides, the results in bladder washings were in high concordance. FISH analysis on bladder washing samples may become a simple tool to improve the accuracy of cytology.

Adult↗

PubMed2000

Precancerous lesions in the kidney.

Renal cell carcinoma (RCC), although occurring less frequently than prostate and bladder cancer, is actually the most malignant urologic disease, killing >35% of affected patients. Therefore, investigation of the nature of premalignant lesions of the kidney is a relevant issue. Following the most recent histological classification RCC can be subdivided into four categories: conventional RCC; papillary RCC; chromophobe RCC; and collecting duct carcinoma. In contrast to many genitourinary malignancies, premalignant alterations in the kidney are scarcely described. Intratubular epithelial dysplasia has been recognized as the most common precursor of RCC. In analogy to prostatic intraepithelial neoplasia (PIN), the premalignant lesions of the kidney are described as high or low-grade renal intratubular neoplasia. In contrast, precancerous lesions have been described as part of the von Hippel-Lindau syndrome (VHL) where the evolution from a simple cyst to an atypical cyst with epithelial hyperplasia to cystic or solid conventional-type RCC is well documented. Finally, in the genesis of papillary RCC an adenoma-carcinoma sequence has been recognized with specific genetic changes. There are no data on the epidemiology of premalignant lesions of the kidney, but research into the etiology of RCC has been extended substantially. Familial and genetic factors are well documented in VHL disease, in hereditary papillary RCC, in the tuberous sclerosis complex and in familial RCC. Cigarette smoking and obesity are established risk factors for RCC. Hypertension or its medication has also been associated with an increased risk. Among dietary factors an inverse relation between risk and consumption of vegetables and fruit has been found. Occupational exposure to substances such as asbestos and solvents has been linked to an increased risk of RCC. Specific RCC variants have distinctive chromosome alterations and several genes have been implicated in the development of RCC. Loss of material from the 3p chromosome characterizes conventional RCC and the deletion of the VHL suppressor gene plays an important role in the genesis of this RCC variant. In contrast, numerical changes with trisomy of chromosomes 7 and 17 and loss of the sex chromosome are typical changes in papillary tumors, whereas papillary RCC have additional trisomies. Chromophobe RCC is characterized by loss of chromosomes with a combination of monosomies. Less consistent genetic alterations are associated with collecting duct carcinoma. The traditional treatment of RCC is surgery by radical or partial nephrectomy. The latter approach carries a risk of tumor recurrence as a result of unrecognized satellite lesions or premalignant lesions that might have been present at the time of surgery. However, the reported recurrence rates after partial nephrectomy are <1% and therefore the possible presence of premalignant disease does not alter the actual treatment strategy advocated. Although multifocality and bilateral occurrence of RCC are much more likely in cases of papillary RCC, biopsy of the renal remnant or contralateral kidney is not justified even in patients with this tumor type. Conversely, patients with RIN in a partial or radical nephrectomy specimen or in a renal biopsy taken for whatever reason should be subjected to closer follow-up with regularly repeated ultrasound. When an effective chemopreventive regimen becomes available it might be useful for patients with an inherited risk of RCC as well as in those who are at risk of tumor recurrence after intervention. Mass screening with the purpose of detecting RCC at its earliest stage is not recommended at the present time, but screening focused on certain risk groups can be advocated. Further research is needed to identify avoidable risks, develop effective chemoprevention and recognize patients at risk.

Carcinoma, Renal Cell↗

PubMed1999

Novel mutations of the MET proto-oncogene in papillary renal carcinomas.

Hereditary papillary renal carcinoma (HPRC) is characterized by multiple, bilateral papillary renal carcinomas. Previously, we demonstrated missense mutations in the tyrosine kinase domain of the MET proto-oncogene in HPRC and a subset of sporadic papillary renal carcinomas. In this study, we screened a large panel of sporadic papillary renal carcinomas and various solid tumors for mutations in the MET proto-oncogene. Summarizing these and previous results, mutations of the MET proto-oncogene were detected in 17/129 sporadic papillary renal carcinomas but not in other solid tumors. We detected five novel missense mutations; three of five mutations were located in the ATP-binding region of the tyrosine kinase domain of MET. One novel mutation in MET, V1110I, was located at a codon homologous to an activating mutation in the c-erbB proto-oncogene. These mutations caused constitutive phosphorylation of MET when transfected into NIH3T3 cells. Molecular modeling studies suggest that these activating mutations interfere with the intrasteric mechanism of tyrosine kinase autoinhibition and facilitate transition to the active form of the MET kinase. The low frequency of MET mutations in noninherited papillary renal carcinomas (PRC) suggests that noninherited PRC may develop by a different mechanism than hereditary papillary renal carcinoma.

3T3 Cells↗

PubMed1991

Molecular genetics and human prostatic carcinoma.

Advances in molecular genetic techniques have reached the point where clinical material can be reasonably well-characterized in detail. One area that is receiving increasing attention is the genetic abnormalities of tumors. Using the technique of restriction fragment length polymorphism analysis, it is possible today to build up a picture of the genome and to identify which regions are deleted or are rearranged in the tumor cells of an individual patient. Twenty years ago, experimental and theoretical findings suggested that loss of gene function could be an essential component in oncogenesis. Such genes have been named tumor suppressor genes. The significance of the consistent loss of specific regions of genetic information from the genomes of tumor cells of a particular histological type is now appreciated, as such areas may contain as yet unrecognized tumor suppressor genes. The characterization of regions consistently lost thus forms the first step in localizing such genes. We have applied this technology to the study of prostate cancer and our preliminary findings show consistent losses of genetic information from chromosomes 8, 10, and 16.

Alleles↗

PubMed1989

Deletion mapping in human renal cell carcinoma.

The highest incidence of renal cell carcinoma (RCC) is reported in Scandinavia. Cytogenetic studies of constitutional tissue in families with hereditary RCC and of sporadic RCC tumor tissue have shown abnormalities of chromosome 3p. In a study of 23 sporadic Scandinavian cases using restriction fragment length polymorphism analysis, we found that 68% of informative patients showed terminal 3p deletions. The break point was not consistent. Loss of a locus on the Y chromosome was seen in 4/14 male patients. Losses of heterozygosity on autosomes included chromosomes 18 (5/15 informative cases) and 17 (3/11 informative cases). Losses in heterozygosity were also found at lower levels for other chromosomes (chromosome 13, 3/16; chromosome 10, 2/19; and chromosome 11, 2/24). The single familial case showed reduplication of part of chromosome 3p and of one chromosome 17. Our data confirm earlier data on losses on chromosome 3p in tumor tissue and by extending this type of analysis to all chromosomes, demonstrate the specificity of this loss. No unique findings were made in the sporadic Scandinavian cases. The results support the thesis that a tumor suppressor gene involved in the oncogenesis of RCC may be located distal to the DNF15S2 locus on chromosome 3p.

Adult↗

PubMedDate not supplied

Comparison of comparative genomic hybridization, fluorescence in situ hybridization and flow cytometry in urinary bladder cancer.

Comparative genomic hybridization (CGH) was applied to screen the genetic events in six invasive urinary bladder cancers. These cases were also studied by flow cytometry (FCM) and fluorescence in situ hybridization (FISH). Four samples showed partial gain on chromosome 8, with the common region involved was on 8q23-qter. Full or partial deletion on chromosome 2 and 17p in addition to gain on 20q was found in two cases. Interestingly one diploid tumor with low mitotic index, stage and grade showed more genetic aberrations (8 gains and 7 losses) by CGH than other aneuploid tumors with high mitotic index, stage and grade. The numerical chromosomal aberration detected by FISH for chromosomes 7, 8, 9, 10, 11 and 17 were 50% in T1 cases and 100% in T2-T4 cases. FISH was performed on chromosome 8q and 17p to compare and validate the sensitivity of CGH. The agreement was 100% for 8q24 locus and 50% for p53 locus. This indicates that different molecular genetic techniques showed relatively different aspect of genomic aberrations.

Chromosome Aberrations↗

PubMedDate not supplied

Somatic mutation and homozygous deletion of PTEN/MMAC1 gene of 10q23 in renal cell carcinoma.

We studied chromosome 10q loss of heterozygosity and PTEN/MMAC1 gene inactivation in renal cell carcinoma (RCC). Fifty-four cases of RCCs were analysed by three 10q RFLP markers. Forty one of them were heterozygous for at least one of the markers, of which fourteen showed LOH (34%). Six tumors which showed 10q deletion for RFLP markers and six randomly selected tumors without RFLP LOH were included in an extended study of 10q by eight microsatellite markers. Eight of these cases showed LOH with two smallest deleted regions (SRO) at 10q23 delineated by markers D10S541 and D10S579 while the other distal SRO is between markers D10S587 and D10S212 at 10q25-26. The five tumors with LOH covering 10q23 were selected for mutation analysis of PTEN/MMAC1 gene. One tumor without LOH of 10q23 was selected as a control. Using direct sequencing of nine exons, we found three different base pair changes in three tumors with LOH. Nine RCC cell lines were analysed for PTEN/MMAC1 gene inactivation. One homozygous deletion was detected in the cell line UOK147. No expression of PTEN/MMAC1 gene was detect by RT-PCR in the cell line UOK 147.

Base Sequence↗

PubMedDate not supplied

Chromosome 8 numerical aberration and C-MYC copy number gain in bladder cancer are linked to stage and grade.

Chromosome 8 aberration and c-myc amplification have been suggested as playing important roles in the development of different human cancers. Using fluorescence in situ hybridization (FISH), chromosome 8 polysomy and c-myc amplification can be detected in cells from bladder cancer. We investigated the correlation of chromosome 8 polysomy, c-myc gene alteration and p53 deletion with histopathological parameters. Twenty-four tumors obtained from patients with bladder cancer were analyzed by interphase cytogenetics using FISH with chromosome 8 and 17 centromere probes together with an YAC clone covering the c-myc locus and three cosmid DNA probes covering the p53 locus. Chromosome 8 polysomy was found in 12 tumors. The average copy number of chromosome 8 centromere signals were significantly higher in high grade and stage, cancers. Also the c-myc copy gain and p53 deletion were significantly correlated with grade as well as stage (p<0.05, in both cases). Both polysomy 8 and c-myc copy gain were significantly correlated with p53 deletions (p<0.01) and DNA ploidy (p<0.001). On the contrary there was no significant correlation between c-myc protein over-expression and c-myc gene amplification. These results may indicate that alteration of chromosomal regions on 8q and 17p, including c-myc and p53 genes, may be linked to progression of bladder cancer.

Carcinoma, Transitional Cell↗